标准编号:	DBJ 15-60-2008
中文名称:	建筑地基基础检测规范
英文名称:	Code for testing of building foundation
行业分类:	DB    地方标准
发布日期:	2008-04-07
实施日期:	2008-5-1
标准状态:	现行
翻译语言:	英文
文件格式:	PDF
中文字符数:	200000 字
翻译价格(元):	19000.00 元
交付时间:	付款后 1 个工作日

Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.



According to the requirements of the document (YUEJIANKEHAN [2002] No.194) issued by Guangdong Provincial Department of Construction, this code was formulated by Guangdong Provincial Academy of Building Research jointly with the organizations concerned through extensive investigation and study, careful summarization of practice experience and scientific research achievements in testing of building foundation, collection and analysis of opinions and suggestions since the implementation of Technical specification of Guangdong Province for quality inspection of pile foundations (Trial) (YUEJIANKEZI [2000] No.137), DBJ 15-27-2000 Specification for reflected wave testing of piles and DBJ 15-28-2001 Technical specification for pile and diaphragm wall inspection with drilled core and on the basis of widely soliciting for opinions.



This code comprises 18 clauses and 8 annexes, including general provisions, terms and symbols, basic requirements, standard penetration test, dynamic penetration test, cone penetration test, vane shear test, plate loading test, low strain integrity testing, high strain dynamic testing, cross hole sonic logging, core drilling method, single-pile vertical compressive static loading test, single-pile vertical pull-out static loading test, single-pile horizontal static loading test, acceptance test of retaining anchor and soil nail, foundation anchor pull-out test, settlement observation, etc.



Guangdong Provincial Academy of Building Research is in charge of the interpretation of this code. During the process of implementing this code, all relevant organizations are kindly requested to sum up experience carefully in combination with engineering practice, and feed the relevant opinions and suggestions back to Guangdong Provincial Academy of Building Research (address: No.121, Xianlie East Road, Guangzhou City, 510500, China; Fax: 02087250256; Email: xtp@21cn.net).





Contents



1 General provisions 1

2 Terms and symbols 2

2.1 Terms 2

2.2 Symbols 5

3 Basic requirements 9

3.1 General requirements 9

3.2 Requirements for subgrade testing 12

3.3 Requirements of testing of foundation pile and foundation anchor 15

3.4 Requirements for supporting engineering testing 19

3.5 Requirements for foundation testing and settlement observation 20

3.6 Verification testing and expanded testing 21

3.7 Testing result evaluation and testing report 23

4 Standard penetration test 25

4.1 Application scope 25

4.2 Equipment 25

4.3 On-site testing 26

4.4 Testing data analysis and judgment 27

5 Dynamic penetration test 31

5.1 Application scope 31

5.2 Equipment 31

5.3 On-site testing 32

5.4 Testing data analysis and judgment 32

6 Cone penetration test 36

6.1 Application scope 36

6.2 Instruments and equipment 36

6.3 On-site testing 37

6.4 Test data analysis and judgment 39

7 Vane shear test 43

7.1 Application scope 43

7.2 Instruments and equipment 43

7.3 On-site testing 44

7.4 Test data analysis and judgment 47

8 Plate loading test 50

8.1 Application scope 50

8.2 Instruments and equipment and their installation 50

8.3 On-site testing 52

8.4 Testing data analysis and judgment 54

9 Low strain integrity testing 57

9.1 Application scope 57

9.2 Instruments and equipment 57

9.3 On-site testing 58

9.4 Testing data analysis and judgment 61

10 High strain dynamic testing 66

10.1 Application scope 66

10.2 Instruments and equipment 66

10.3 On-site testing 67

10.4 Testing data analysis and judgment 69

11 Cross hole sonic logging 75

11.1 Application scope 75

11.2 Instruments and equipment 75

11.3 Embedding of sonic logging pipe 76

11.4 On-site testing 77

11.5 Testing data analysis and judgment 79

12 Core drilling method 90

12.1 Application scope 90

12.2 Equipment 90

12.3 On-site operation 91

12.4 Core specimen taking and processing 93

12.5 Compressive strength test of core specimen 94

12.6 Testing data analysis and judgment 95

13 Single-pile vertical compressive static loading test 100

13.1 Application scope 100

13.2 Instruments and equipment and their installation 100

13.3 On-site testing 102

13.4 Testing data analysis and judgment 105

14 Single-pile vertical pull-out static loading test 107

14.1 Application scope 107

14.2 Instruments and equipment and their installation 107

14.3 On-site testing 109

14.4 Testing data analysis and judgment 111

15 Single-pile horizontal static loading test 113

15.1 Application scope 113

15.2 Instruments and equipment and their installation 113

15.3 On-site testing 114

15.4 Testing data analysis and judgment 115

16 Acceptance test of retaining anchor and soil nail 118

16.1 Application scope 118

16.2 Instruments and equipment and their installation 118

16.3 On-site testing 120

16.4 Testing data analysis and judgment 122

17 Foundation anchor pull-out test 125

17.1 Application scope 125

17.2 Instruments and equipment and their installation 125

17.3 On-site testing 126

17.4 Test data analysis and judgment 128

18 Settlement observation 129

18.1 Application scope 129

18.2 Observation grade and instruments and equipment 129

18.3 Setting of bench mark and observation point 131

18.4 Site observation 133

18.5 Data analysis and evaluation 134

Annex A Testing record form of building foundation 137

Annex B Statistical calculation method of foundation soil test data 142

Annex C Correction of the blow count of dynamic penetration test 144

Annex D Calibration of cone penetration probe 146

Annex E Treatment of concrete pile head 148

Annex F Installation of sensors for high strain dynamic testing 149

Annex G Pile driving test and pile driving monitoring in high strain dynamic testing 151

G.1 Pile driving test 151

G.2 Hammer stress monitoring of pile shaft 151

G.3 Hammer energy monitoring 153

Annex H Processing and measurement of concrete core specimens 154

Explanation of wording in this code 156





1 General provisions



1.0.1 This code is formulated with a view to improving the testing level of building foundation, unifying the testing methods of building foundation, ensuring the engineering testing quality, and achieving safety, applicability, data accuracy, advanced technology, economic feasibility, and environmental protection.



1.0.2 This code is applicable to the acceptance testing of foundations of construction engineering in Guangdong Province. It may also be referred to for the testing of foundations for other purposes and other industries.



1.0.3 For the testing of building foundation, the testing methods shall be selected reasonably and the testing quantity shall be determined with comprehensive consideration of factors such as geological conditions, foundation design grade, foundation type, construction quality reliability, and characteristics and application scope of various testing methods.



1.0.4 In addition to this code, the testing of building foundation shall also comply with the compulsory provisions of national engineering construction standards.



 

2 Terms and symbols



2.1 Terms



2.1.1 subgrade, foundation soils

soil or rock mass supporting the foundation



2.1.2 natural foundation, natural subgrade

subgrade with the foundation directly built on the natural soil (rock) layer without manual treatment, which may be divided into natural soil subgrade and natural rock subgrade



2.1.3 the foundation of treatment soils

subgrade with soil subjected to manual treatment in order to increase the bearing capacity of the subgrade and improve the deformation property or permeability, which includes replacement subgrade, preloaded subgrade, dynamic consolidation subgrade, vibroflotation compaction subgrade without additional backfill materials, grouting subgrade, etc.



2.1.4 composite subgrade, composite foundation

subgrade of which some soil is reinforced or replaced to form a reinforcement that together with the surrounding foundation soil bears the load



2.1.5 foundation pile

single pile in pile foundation



2.1.6 anchor

tensile member composed of tensile materials such as steel bars or steel strands which are arranged in the borehole and whose ends are extended into the stable rock-soil layer, and grouting body in the borehole



2.1.7 retaining anchor

anchor transferring the lateral load borne by the envelop enclosure to the surrounding stable rock-soil layer through the tie effect of the anchor



2.1.8 foundation anchor

anchor transferring the upward vertical load borne by the foundation to the stable rock-soil layer at the bottom of the foundation through the tie effect of the anchor



2.1.9 soil anchor

anchor with anchorage section set in soil stratum



2.1.10 rock anchor

anchor with anchorage section set in rock



2.1.11 soil nail

slender member used to reinforce and anchor the in-situ soil mass at the same time, which, relying on the interfacial adhesion or friction with soil mass, is passively stressed under the condition of deformation of the soil mass to mainly bear the tensile force



2.1.12 standard penetration test (SPT)

an in-situ test method to judge the physical and mechanical properties of soil by pre-driving a standard penetrator 15cm into the bottom of the borehole by using a 63.5kg penetration hammer from a falling distance of 76cm, and then recording the blow count required for driving the penetrator for another 30cm



2.1.13 dynamic penetration test (DPT)

an in-situ test method to judge the physical and mechanical properties of soil according to the blow count required for driving a standard conical probe a certain distance into soil by using a heavy hammer from a certain falling distance



2.1.14 cone penetration test (CPT)

an in-situ test method to judge the physical and mechanical properties of soil according to the penetration resistance of a standard conical probe determined when pressing this probe into soil at a constant speed by static force



2.1.15 vane shear test (VST)

an in-situ test method to determine the undrained shear strength of soil by measuring the resistance moment of soil at the time of being damaged with a standard vane probe inserted into the soil



2.1.16 plate loading test (PLT)

test method for determining the bearing capacity of natural subgrade, the foundation of treatment soils, composite subgrade by applying vertical pressure step by step on the surface of subgrade and measuring the change of subgrade settlement with time



2.1.17 low strain integrity testing

testing method for judging the pile integrity through wave theory analysis based on the velocity-time history curve of the pile top which is obtained by measuring when exciting the pile top with the low-energy transient excitation method



2.1.18 high strain dynamic testing

testing method for judging the vertical compressive bearing capacity of single pile and pile integrity through wave theory analysis based on the velocity-time history curve of the upper part of the pile which is obtained by measuring when impacting the pile top with a heavy hammer



 

2.1.19 cross hole sonic logging

testing method for judging the pile integrity and diaphragm wall integrity based on the relative changes of acoustic parameters such as acoustic time, frequency and amplitude attenuation of acoustic waves propagating in concrete medium which are measured by transmitting and receiving acoustic waves between embedded sonic logging pipes



2.1.20 core drilling method

testing method for judging the object integrity, the strength of core specimens, the bottom sediment thickness and the geotechnical properties of bearing stratum by drilling core samples of the vertical reinforcement of composite subgrade, the diaphragm wall, and the cast-in-situ concrete pile and its bearing stratum by drilling machine



2.1.21 static loading test

test method for determining the corresponding vertical compressive bearing capacity, vertical pull-out bearing capacity and horizontal bearing capacity of single pile according to the settlement, uplift displacement or horizontal displacement of the pile top over time which are obtained by observing when applying vertical pressure, vertical uplift force or horizontal thrust onto the pile top step by step



2.1.22 settlement observation

observation method for measuring the change of settlement of buildings (structures) with time



2.1.23 pile integrity

a comprehensive qualitative index reflecting the relative change of pile sectional dimension, and the compactness and continuity of pile material



2.1.24 pile defects

a general name for pile fracture, crack, diameter reduction, mud (sundry) inclusion, cavity, honeycomb, looseness and other phenomena



2.1.25 wave measure line

the connecting line between measuring points in two acoustic measuring channels of a certain testing section



2.1.26 the function value of wave measure line's integrity

value determined according to the acoustic parameters and waveform distortion degree of acoustic waves received on the wave measure line, ranging from 1 to 4, and reflecting the pile concrete quality in the sound field radiation area of the wave measure line



2.1.27 the exponent of pile cross section's integrity grade

an index reflecting the concrete integrity of a pile cross section, ranging from 1 to 4, which is obtained by comprehensively taking into account each function value of wave measure line's integrity on this cross section

2.2 Symbols



2.2.1 Resistance and material properties



c——the propagation velocity of one-dimensional longitudinal stress wave of pile (referred to as “pile shaft wave velocity” for short);



Cu——the undrained shear strength of foundation soil;



E——the elastic modulus of pile shaft;



E0——the modulus of deformation of subgrade;



fak——the characteristic value of subgrade bearing capacity;



fcu——the compressive strength of concrete core specimen;



fs——the side frictional resistance of double bridge probe;



fspk——the characteristic value of bearing capacity of composite subgrade;



m——the proportionality coefficient of foundation soil horizontal resistance coefficient;



N——the corrected blow count of standard penetration test;



N′——the measured blow count of standard penetration test;



Nk——the standard value of blow count of standard penetration test;



N10——the blow count of light dynamic penetration test;



N63.5——the blow count of heavy dynamic penetration test;



N120——the blow count of extra-heavy dynamic penetration test;



Nu——the design value of the axial tensile bearing capacity of anchor;



p——the characteristic value of subgrade bearing capacity;



ps——the specific penetration resistance of single bridge probe;



qc——the cone head resistance of double bridge probe;



Qu——the single-pile vertical ultimate bearing capacity;



Ra——the characteristic value of singe-pile vertical compressive bearing capacity; kN;



Rt——the characteristic value of pull-out bearing capacity of anchor;



v——the sound velocity of pile shaft concrete;



Z——the mechanical impedance of pile shaft section;



μ——the Poisson's ratio of soil;



ρ——the mass density of pile shaft.



2.2.2 Actions and action effects



F——the hammer force;



H——the horizontal force acting on pile shaft in single-pile horizontal static loading test;



Nmax——the maximum test load of anchor;



Pf——the total acting force of shear-damage soil mass;



Q——the vertical compressive load applied onto single pile and subgrade, and the axial tensile load applied onto anchor;



s——the settlement;



U——the uplift load applied in single-pile vertical pull-out static loading test;



V——the velocity of particle motion;



Y0——the horizontal displacement of pile shaft in the horizontal force acting plane in single-pile horizontal static loading test;



δ——the pile top uplift amount and anchor head displacement in single-pile vertical pull-out static loading test.



2.2.3 Geometric parameters



A——the cross-sectional area of pile shaft;



b——the side width of rectangular pile, or the diameter or side width of bearing plate;



b0——the calculated width of pile shaft;



B——the width of pier, or the side width of support;



d——the diameter of pile shaft (outer diameter of pipe pile), or the average diameter of core specimen;



L——the pile length.



2.2.4 Calculation coefficients



Ac——the critical value for judgment of abnormal amplitude in cross hole sonic logging;



Jc——the damping coefficient for CASE method;



α——the correction coefficient, the friction-resistance ratio (%), or the horizontal deformation coefficient of pile;



β——the pile integrity coefficient for high strain dynamic testing;



λ——the coefficient corresponding to different statistical numbers in the sample;



vy——the horizontal displacement coefficient of pile top;



ξ——the conversion coefficient for compressive strength of concrete core specimen.



2.2.5 Others



Ap——the acoustic wave amplitude;



α——the peak voltage of the first wave of acoustic wave signal;



f——the frequency;



n——the sample size;



T——the signal period;



t——the time;



v0——the abnormal judgment value of sound velocity;



v01——the judgment value of abnormal small value;



v02——the judgment value of abnormal large value;



vc——the critical value for judgment of abnormal sound velocity;



vL——the low limit value of sound velocity of pile shaft concrete;



Δf——the frequency difference between adjacent peaks on the frequency domain curve;



Δt——the time difference between the incident wave peak and the reflected wave peak.



 

3 Basic requirements



3.1 General requirements



3.1.1 For the acceptance of building foundation engineering, quality testing shall be conducted in accordance with those specified in this code.



3.1.2 The testing of building foundation engineering is classified into subgrade testing, foundation pile and foundation anchor testing, supporting engineering testing and foundation testing. The testing methods shall be selected reasonably according to the testing purpose.



1 Subgrade testing. The testing content includes: evaluation of bearing capacity, deformation parameters and geotechnical properties of natural subgrade; evaluation of bearing capacity, deformation parameters and construction quality of the foundation of treatment soils; and evaluation of bearing capacity, deformation parameters and reinforcement construction quality of composite subgrade. The testing methods may be selected from plate loading test, core drilling method, standard penetration test, dynamic penetration test, cone penetration test, vane shear test, geotechnical test, low strain integrity testing, deep plate loading test and rock foundation loading test.



2 Foundation pile and foundation anchor testing. The testing content includes: pile integrity and bearing capacity testing of engineering pile, and pull-out bearing capacity testing of foundation anchor. The pile integrity testing may be conducted with core drilling method, cross hole sonic logging, high strain dynamic testing, low strain integrity testing, etc. The single-pile vertical compressive bearing capacity testing may be conducted with single-pile vertical compressive static loading test and high strain dynamic testing; the single-pile vertical pull-out bearing capacity testing may be with single-pile vertical pull-out static loading test; the single-pile horizontal bearing capacity testing may be with single-pile horizontal static loading test; the pull-out bearing capacity testing of foundation anchor may be with foundation anchor pull-out test.



3 Supporting engineering testing. The testing content includes: pull-out force testing of soil nail and retaining anchor, construction quality testing of soil nail wall, integrity testing of cement-soil wall, quality testing of diaphragm wall, construction quality testing of reverse arch wall, and pile integrity testing of cast-in-situ concrete pile for supporting. The testing methods may be selected from acceptance test of soil nail and retaining anchor, core drilling method, cross hole sonic logging, and low strain integrity testing.



4 Foundation testing. The testing content includes: construction quality testing of various foundations and pile caps, and building settlement observation. Concrete strength may be tested with structural core drilling method and rebound method.

 

3.1.3 The testing work procedures shall be carried out in accordance with Figure 3.1.3.







Figure 3.1.3 Block diagram of testing work



3.1.4 Investigation and data collection should include:



1 Collecting geotechnical investigation data, foundation design and construction data of the tested engineering; understanding the construction technology and the abnormal conditions during construction.



2 Further clarifying the specific requirements of the entrusting party.



3 Analyzing the feasibility of on-site implementation of testing items.



3.1.5 The testing unit shall select the testing methods and formulate the testing plan according to the investigation results and the determined testing purpose. The testing plan should include the engineering overview, testing methods and applicable specifications and standards, testing quantity, sampling plan, the required mechanical equipment and manpower coordination, and test time requirements, and shall also include the requirements of pile head excavation, reinforcement, treatment, site leveling, road construction, water supply and power supply, etc. where necessary.



Where it is judged that the selected testing method cannot meet the testing purpose based on the results of the on-site test, the testing method shall be re-selected and a testing plan should be developed. The testing results that fail to fully meet the testing purpose shall not be included in the sampling quantity.



3.1.6 The sampling quantity for acceptance testing of foundation engineering shall be calculated according to unit works. When a unit work is composed of several sub-unit works, the sampling quantity should be calculated according to the sub-unit works.



If different foundation types are used in the same unit work, the testing methods and sampling quantity shall be determined separately. If different pile types or different subgrade treatment methods are adopted in the same unit work, the testing methods and sampling quantity should be determined respectively.



For a residential area work with the foundation design grade of Grade C and the total number of engineering piles being less than 30 or the subgrade treatment area being less than 300m2 in each unit work, several unit works with similar geological conditions and the same construction technology may be combined to determine the sampling quantity upon joint confirmation by the responsible subjects of all parties involved in work quality, but each unit work shall be subjected to sampling testing for bearing capacity, of which the sampling quantity shall not be less than: 1 pile in case of static loading test, 2 piles in case of high strain dynamic testing, and 2 points in case of plate loading test.



For a large-scale unit work with the subgrade treatment area exceeding 20,000m2 or the total number of engineering piles exceeding 2,000, the sampling quantity of the excess part may be appropriately reduced, but it shall not be less than 50% of the corresponding prescribed sampling quantity.



The repaired pile and reinforced pile shall be subjected to sampling testing.



3.1.7 When the testing data is abnormal or there is doubt about the testing results, the reasons shall be found and the testing shall be conducted again if necessary. Standard penetration test, cone penetration test, dynamic penetration test and vane shear test may be carried out again at the point near the original test hole, while low strain integrity testing, high strain dynamic testing and cross hole sonic logging may be carried out again on the original tested pile.



3.1.8 The measuring instruments for testing shall be calibrated. The performance of instruments and equipment shall meet the technical requirements of corresponding testing methods.



When the instruments and equipment are being used, the relevant parameters shall be set according to the calibration results.



Before testing, the instruments and equipment shall be inspected and debugged; during testing, the inspection on instruments and equipment shall be strengthened. The instruments and equipment shall be calibrated where necessary before and during testing.



3.1.9 During on-site testing, in addition to the relevant requirements of this code, the relevant regulations of the nation on safety production shall also be complied with; when the on-site operation environment does not meet the use requirements of instruments and equipment, effective measures shall be taken to ensure the normal operation of instruments and equipment.



3.2 Requirements for subgrade testing



3.2.1 The natural soil subgrade, foundation of treatment soils and composite subgrade shall be subjected subgrade testing by two or more testing methods reasonably, and the testing shall follow the principle of from simple to complex, from thick to fine, and from surface before point.



3.2.2 The testing of the foundation of treatment soils and the composite subgrade should be carried out with a reasonable intermittent time.



3.2.3 The sampling position for subgrade testing shall be comprehensively determined according to the following conditions:



1 The part where any abnormal condition occurs during construction;



2 The part deemed important by the design;



3 The part with complicated local geotechnical characteristics that may affect the construction quality;



4 When two or more testing methods are adopted, the sampling position of the latter method shall be determined according to the testing results of the former method;



5 The sampling positions of similar subgrades should be evenly distributed.



3.2.4 The natural rock subgrade shall be subjected to sampling testing with core drilling method, and the sampling quantity per unit work shall not be less than 6 holes, the drilling depth shall meet the design requirements, and a group of three core specimens shall be taken from the core sample of each hole. For the natural rock subgrade work with complex characteristics, the number of sampling holes shall be increased. When the rock core sample cannot be made into core specimen, rock foundation loading test shall be carried out, and plate loading test should be adopted for strongly weathered rock and completely weathered rock, and the number of test points shall not be less than 3.



3.2.5 The natural soil subgrade and the foundation of treatment soils shall be subjected to plate loading test, and the sampling quantity for unit work shall be neither less than 1 point per 500m2 nor less than 3 points. For complex sites or important building foundations, the sampling quantity shall be increased.



3.2.6 Before plate loading test, the natural soil subgrade and the foundation of treatment soils shall be subjected to a general testing for their treatment quality or the natural foundation soil properties by one or more methods among standard penetration test, dynamic penetration test, cone penetration test and vane shear test according to the subgrade type, and the sampling quantity shall be neither less than 1 hole per 200m2 nor less than 10 holes for unit work, shall not be 1 hole for each independent plinth, and shall not be less than 1 hole per 20 linear meters for foundation trench. The testing depth shall meet the design requirements.



When there is no engineering practice experience available, the testing may be carried out according to the following requirements:



1 After the foundation trench (pit) of natural subgrade is excavated, the foundation trench (pit) may be tested by standard penetration test, dynamic penetration test, cone penetration test or other methods.



2 The replacement subgrade (including lime-soil subgrade, sand and sandstone subgrade, geosynthetic subgrade, flyash subgrade) may be tested by dynamic penetration test or standard penetration test.



The replacement subgrade must be tested for its compacting factor by layers with the cutting-ring method, sand filling method, water filling method or other methods specified in GB/T 50123 Standard for geotechnical testing method, and the sampling quantity shall not be less than: 1 point per 50~100m2 in case of large foundation pit, 1 point per 10~20m in case of foundation trench, and 1 point for each independent plinth.



3 The preloaded subgrade may be tested by vane shear test and indoor geotechnical test.



4 The dynamic consolidation subgrade may be tested by in-situ testing and indoor geotechnical test.



5 The vibroflotation compaction subgrade without additional backfill materials may be tested by dynamic penetration test, standard penetration test or other methods.



6 The grouting subgrade may be tested by standard penetration test and core drilling method.



 

3.2.7 The composite subgrade and the dynamic replacement pier shall be subjected to the plate loading test of composite subgrade, and the sampling quantity for unit work shall be 0.5%~1% of the total number of piles (piers) but no less than 3 points. The plate loading test of composite subgrade of the same unit work may be carried out in the form of plate loading test of multi-pile composite subgrade or that of single-pile (pier) composite subgrade, or in the form of plate loading test of multi-pile composite subgrade at some test points and plate loading test of single-pile composite subgrade at the other test points.



3.2.8 Before the plate loading test, the composite subgrade and the dynamic replacement pier shall be tested for the pile shaft construction quality of composite subgrade with appropriate testing method, and the sampling quantity shall be: 0.5%~1% of the total number of piles (piers) but no less than 3 for the unit work in the case that standard penetration test, dynamic penetration test and other methods are adopted; neither less than 0.5% of the total number of piles nor less than 3 in the case that single-pile vertical compressive static loading test and core drilling method are adopted. The testing methods and sampling quantity shall also meet the following requirements:



1 Cement-soil mixing pile and vertical load-bearing jet grouting pile shall be subjected to single-pile vertical compressive loading test;



2 The construction quality of cement-soil mixing pile and jet grouting reinforcement shall be tested by core drilling method;



3 The cement flyash gravel pile shall be subjected to pile integrity testing by low strain integrity testing or core drilling method, and the sampling quantity of low strain integrity testing shall not be less than 10% of the total number of piles;



4 The shaft quality of vibroflotation pile shall be tested by dynamic penetration test or single-pile loading test. The shaft quality of gravel pile shall be tested by heavy dynamic penetration test;



5 The shaft quality of sand-gravel pile shall be tested by dynamic penetration test or other methods. The sand-gravel pile should be subjected to single-pile loading test;



6 The dynamic replacement subgrade shall be tested by dynamic penetration test or other methods.



3.2.9 When required by the design, the soil between piles of composite subgrade and soil between dynamic replacement piers shall be subjected to sampling testing, and the testing methods and sampling quantity should refer to those specified in 3.2.5 and 3.2.6.



 

3.3 Requirements of testing of foundation pile and foundation anchor



3.3.1 The acceptance of engineering piles shall include pile integrity testing and single-pile bearing capacity testing.



The pile integrity testing should be carried out first and then the bearing capacity testing be carried out; when the buried depth of foundation is large, the pile integrity testing should be carried out after the foundation pit is excavated to the base elevation.



3.3.2 The intermittent time from pile formation to the start of the test shall meet the following requirements:



1 When the low strain integrity testing or the cross hole sonic logging is adopted, the concrete strength of the pile shaft to be tested shall not be less than 70% of the design strength grade or the strength of the reserved test cube shall not be less than 15MPa.



2 When the core drilling method is adopted, the concrete age of the pile to be tested shall not be less than 28d or the strength of the reserved test cube shall not be less than design strength grade.



3 The intermittent time of high strain dynamic testing and static loading test shall be as follows: the concrete age of cast-in-situ concrete pile shall not be less than 28d; in case of precast pile (steel pile), the intermittent time after pile formation should not be less than 7d for sandy soil, 10d for silty soil, 15d for unsaturated cohesive soil, 25d for saturated cohesive soil, and 25d for pile tip bearing stratum which is weathered rock easy to soften when exposed to water.



3.3.3 The piles subject to sampling testing for pile integrity and single-pile bearing capacity should be comprehensively determined according to the following conditions:



1 Pile with questionable construction quality;



2 Pile deemed important by the design;



3 Pile with abnormal local geological conditions;



4 When two or more testing methods are adopted, the to-be-tested piles of the latter method should be determined according to the testing results of the former method;



5 The piles of the same type should be evenly distributed.



3.3.4 The sampling quantity of the pile integrity testing for cast-in-situ concrete pile shall meet the following requirements:



1 For three-pile or less cap under column, the sampling quantity of piles per cap shall not be less than 1.



2 When one of the following conditions is met, the sampling quantity of piles for four-pile or more cap under column shall not be less than 30% of the total number of piles, and the total number of piles tested for unit work shall not be less than 20.



1) Foundation pile work with foundation design grade A;



2) Pile foundation work with complex geological conditions on site;



3) Pile foundation work with low reliability of construction quality caused by construction technology;



4) New pile types adopted in this area or pile foundation work constructed by new technology.



For other works, the sampling quantity of piles for four-pile or more cap under column shall not be less than 20% of the total number of piles, and the total number of piles tested for unit work shall not be less than 10.



3 For end-bearing cast-in-situ concrete piles with a diameter greater than or equal to 800mm, some of the tested piles shall be subjected to pile integrity testing by core drilling method or cross hole sonic logging, and the sampling quantity shall not be less than 10% of the total number of piles, within the range specified in the above two items.



4 When the test data is inadequate to evaluate the quality of the whole tested pile shaft and the integrity grade of the pile shaft cannot be determined, this pile shall not be included in the sampling quantity of piles specified in the above three items, and the tested piles shall be re-determined or the testing method shall be re-selected to ensure that the sampling quantity of piles meets the requirements of this subclause.



3.3.5 The single-pile vertical compressive bearing capacity testing for cast-in-situ concrete pile shall meet the following requirements:



1 In case of static loading test, the sampling quantity shall be neither less than 1% of the total number of piles nor less than 3; if the total number of piles is less than 50, the sampling quantity shall not be less than 2. In case of high strain dynamic testing, the sampling quantity shall be neither less than 5% of the total number of piles nor less than 5.



2 Under one of the following conditions, the single-pile vertical compressive bearing capacity testing shall be carried out by static loading test:



1) Foundation pile work with foundation design grade A;



2) Pile foundation work with complex geological conditions on site;



3) Pile foundation work with low reliability of construction quality caused by construction technology;



4) There are obvious pile defects, which have an influence on the bearing capacity of the pile shaft structure, and it is difficult to determine the degree of influence by using the integrity testing method;



5) New pile types adopted in this area or pile foundation work constructed by new technology.



3 For end-bearing cast-in-situ concrete piles with a diameter greater than or equal to 1,500mm, if it is difficult to carry out single-pile vertical compressive bearing capacity testing due to the limitation of test equipment or site conditions upon joint confirmation by the responsible subjects of all parties involved in work quality, the pile integrity testing and the identification of pile tip bearing stratum shall be carried out, for which the testing methods shall be core drilling method, cross hole sonic logging or high strain dynamic testing. The total sampling quantity of piles shall meet the requirements of 3.3.4, among which the sampling quantity for core drilling method shall be neither less than 10% of the total number of piles nor less than 10. If the rock foundation loading test (no less than 3 points) has been carried out before pile formation, the total sampling quantity of piles may be reduced by 2%.



3.3.6 The pile integrity testing and single-pile vertical compressive bearing capacity testing for precast piles shall meet the following requirements:



1 When conditions permit, the pile integrity should be tested by using in-hole camera or by putting a low-voltage bulb into the inner cavity of pipe pile.



2 For precast pile work meeting one of the following conditions, the pile integrity testing and single-pile vertical compressive bearing capacity testing shall be carried out by low strain integrity testing and static loading test respectively, and the sampling quantity for integrity testing shall not be less than 20% of the total number of piles, and that for static loading test shall be neither less than 1% of the total number of piles not less than 3; if the total number of piles is less than 50, the sampling quantity shall not be less than 2.



1) Pile foundation work with karst geological conditions on site;



2) Precast pile work in non-karst area, of which the overlying soil stratum is soft soil stratum such as sludge, and under which it is moderately weathered rock or slightly weathered rock, or only thin strongly weathered rock on the moderately weathered rock surface;



3) The pile tip bearing stratum is weathered rock stratum that is easy to soften when exposed to water;



4) Pile foundation work constructed by "pre-augering method".



3 For precast pile works other than those specified in Item 2 of this subclause, the pile integrity testing and single-pile vertical compressive bearing capacity testing shall be carried out at the same time with the high strain dynamic testing, for which the sampling quantity shall be neither less than 8% of the total number of piles under the same conditions nor less than 10. For Grade B pipe pile foundation works with foundation design grade A and complex geological conditions, the sampling quantity shall be increased by 1%. For the pile foundation works that meet one of the following conditions, the sampling quantity may be reduced by 1%:



1) Pile foundation work of which the welds have been subjected to sampling testing according to relevant specifications;



2) Prestressed pipe pile work which has been subjected to pile integrity testing with in-hole camera or low-voltage bulb, with a sampling quantity exceeding 80% of the total number of engineering piles, but has no obvious quality defects found;



3) Prestressed pipe pile work with mechanical joints;



4) Pile foundation work with automatic pile driving recording equipment for construction record during the construction process.



Note: In the case that high strain dynamic testing is not used for sampling testing, the testing method and the sampling quantity of piles shall meet the requirements of Item 2 in this subclause.



3.3.7 The steel piles shall be tested by high strain dynamic testing and static loading test. For high strain dynamic testing, the sampling quantity shall be neither less than 5% of the total number of piles nor less than 10; for static loading test, the sampling quantity shall be neither less than 0.5% of the total number of piles nor less than 3, and if the total number of piles is less than 50, the sampling quantity shall not be less than 2.



3.3.8 For the engineering piles of which the pile driving process is monitored by high strain dynamic testing or the test piles subjected to static loading test before construction, if the construction technology of test piles is the same as that of engineering piles and the pile shaft is undamaged and the single-pile vertical compressive bearing capacity is greater than or equal to 2 times the characteristic value of singe-pile vertical compressive bearing capacity, half of this kind of test piles may be included in the sampling quantity for acceptance test with the same method.



3.3.9 The pile foundation work that has design requirements for vertical pull-out bearing capacity shall be subjected to the single-pile vertical pull-out static loading test. The sampling quantity of piles shall be neither less than 1% of the total number of piles nor less than 3.



3.3.10 The pile foundation work that has design requirements for horizontal bearing capacity shall be subjected to the single-pile horizontal static loading test. The sampling quantity of piles shall be neither less than 1% of the total number of piles nor less than 3.



3.3.11 The foundation anchors shall be subjected to pull-out test, for which the sampling quantity shall be neither less than 5% of the total number of anchors nor less than 6.



3.4 Requirements for supporting engineering testing



3.4.1 The retaining anchors shall be subjected to acceptance test, for which the sampling quantity shall be neither less than 5% of the total number of anchors nor less than 6.



3.4.2 For the purpose of quality acceptance, the soil nail wall shall be subjected to soil nail pull-out test, for which the sampling quantity shall be 0.5%~1% of the total number of soil nails but shall not be less than 10. The thickness of shotcrete on wall surface shall be tested by drilling method, and the sampling quantity should be one group per 100m2 wall area, with no less than 3 points in each group.



3.4.3 The cast-in-situ concrete piles for supporting shall be subjected to pile integrity testing, for which the sampling quantity should be neither less than 10% of the total number of piles nor less than 10, and the testing method may be low strain integrity testing; if pile defects judged by low strain integrity testing possibly affect the horizontal bearing capacity of the pile, supplementary testing shall be conducted with core drilling method, and the sampling quantity should be neither less than 2% of the total number of piles nor less than 3.



3.4.4 The cement-soil wall shall be subjected to integrity testing by the core drilling method, the sampling quantity should be neither less than 1% of the total number of piles nor less than 5, and core sample shall be taken for compressive strength test.



3.4.5 The diaphragm wall shall be tested for integrity with cross hole sonic logging and core drilling method. When the diaphragm wall is part of a permanent structure, the sampling quantity shall be neither less than 20% of the total number of groove sections nor less than 3 groove sections; when the diaphragm wall is a temporary structure, the sampling quantity shall be neither less than 10% of the total number of groove sections nor less than 3 groove sections.

 

3.4.6 The construction quality of reverse arch wall shall be tested, for which the sampling quantity shall be one group per 100m2 wall surface, with no less than 3 points in each group, and the testing method may be structural core drilling method.



3.5 Requirements for foundation testing and settlement observation



3.5.1 The spread foundation, strip foundation under column, raft foundation and pile foundation cap shall be tested for concrete strength, and the sampling quantity for unit work shall be neither less than 10% of the total number of members nor less than 3 members. The testing methods may be core drilling method and rebound method. In case of core drilling method, the number of core drilling holes shall not be less than 3 per member (not less than 2 for the member with small sectional dimension), and one core specimen shall be taken each hole.



3.5.2 The reinforced concrete foundation and pile foundation cap should be tested for the protective cover thickness, and the sampling quantity for unit work should not less than 10% of the total number of members.



3.5.3 The following buildings shall be subjected to settlement observation until the settlement reaches the stable standard:



1 Buildings with foundation design grade A;



2 Buildings with the design grade of foundation above composite subgrade or soft subgrade being B;



3 Buildings that have serious quality problems on the foundation and have undergone engineering treatment;



4 Adjacent buildings affected by construction;



5 Buildings affected by environmental factors such as groundwater on site;



6 Renovated and expanded engineerings and storey-adding engineerings;



7 Buildings with new foundation or new structure;



8 Buildings whose design requires settlement observation.



 

3.6 Verification testing and expanded testing



3.6.1 If there is any objection to the testing results, testing shall be carried out again at the point near the original test point, or verification testing may be carried out on the original tested pile. The sampling quantity for verification testing should be determined according to the actual situation. The verification testing shall meet the following requirements:



1 The subgrade bearing capacity results of standard penetration test, cone penetration test, dynamic penetration test, vane shear test, etc. may be comprehensively analyzed and evaluated according to the results of plate loading test;



2 The shallow defects of pile shaft may be verified by excavation;



3 Precast piles with defects in pile shaft or joint may be verified by high strain dynamic testing. When necessary, horizontal loading test or vertical pull-out static loading test shall be conducted.



4 The testing results of low strain integrity testing may be verified by core drilling method and high strain dynamic testing;



5 If there is any objection to the testing results of cross hole sonic logging, the cross hole sonic logging may be re-conducted, or verification may be conducted on the same foundation pile with core drilling method;



6 Drill hole may be added in the same foundation pile to verify the testing results of core drilling method;



7 The single-pile bearing capacity results of high strain dynamic testing may be verified by single-pile vertical compressive static loading test.



3.6.2 When the testing results do not meet the design requirements, expanded sampling testing shall be carried out, for which the original sampling testing method or the testing method with higher accuracy shall be adopted. In the case that the cross hole sonic logging can't be used for expanded testing because no sonic logging pipe is buried, the core drilling method shall be adopted. The sampling quantity for expanded testing should be twice the number of piles that fail to meet the design requirements:



1 If the sampling testing results of plate loading test, anchor and soil nail test, single-pile bearing capacity test or core drilling method fail to meet the design requirements, expanded testing shall be carried out with a sampling quantity twice the number of members that fail to meet the design requirements.

 

2 If the sum of Grades III and IV piles found in pile integrity testing by low strain integrity testing is greater than 20% of the sampling quantity of piles, expanded testing shall be carried out per the original sampling ratio; and if the sum of Grades III and IV piles in two sampling testings is still greater than 20% of the sampling quantity of pile, all piles of this batch shall be tested. If not, the treatment scheme or the method and quantity of expanded sampling testing shall be studied and determined.



3 If the sum of Grades III and IV piles found in pile integrity testing by high strain dynamic testing and cross hole sonic logging is greater than 20% of the sampling quantity of piles, expanded testing shall be carried out per the original sampling ratio. If not, the treatment scheme or the method and quantity of expanded sampling testing shall be studied and determined.



4 If more than 30% of the testing holes for standard penetration test, dynamic penetration test, cone penetration test, vane shear test or other methods fail to meet the design requirements, expanded testing shall be carried out with a sampling quantity twice the number of holes failing to meet the design requirements, or the number of holes for plate loading test shall be appropriately increased.



5 If the concrete strength testing results of spread foundation, strip foundation under column, raft foundation and pile foundation cap fail to meet the design requirements, expanded testing shall be carried out with a sampling quantity twice the number of members failing to meet the design requirements. The testing method should be core drilling method.



Notes: 1 When the testing results of precast pile fail to meet the design requirements, all the precast piles may be re-driven or re-pressed, and then sampling testing shall be carried out again according to the requirements of 3.5;



2 When the testing results meet the revised design requirements, expanded sampling testing may not be carried out.



3.6.3 After the verification testing and the first expanded sampling testing, the supervision organization or development organization shall study and determine the treatment scheme or the method and quantity for further sampling testing according to the test results in conjunction with the testing, investigation, design and construction organizations.



If there is any doubt or dispute about the testing results, but the conditions for re-testing and verification testing are not available, the supervision organization or development organization shall study and determine the treatment scheme in conjunction with the testing, investigation, design and construction organizations.



 

3.7 Testing result evaluation and testing report



3.7.1 In case of standard penetration test, cone penetration test, dynamic penetration test and vane shear test, the testing result of each test hole and the evaluation results of main soil strata of unit work shall be given.



3.7.2 In case of plate loading test, the characteristic value of bearing capacity at each point and the characteristic value of subgrade bearing capacity of unit work as well as the conclusion whether the characteristic value of subgrade bearing capacity of unit work meeting design requirements shall be given.



3.7.3 The pile integrity testing results shall include the integrity grade of each tested pile. The pile integrity graduation shall be in accordance with those specified in Table 3.7.3 and shall be graded according to the technical contents specified in Clauses 9~12 respectively.



Table 3.7.3 Pile integrity graduation

Pile integrity grade Graduation principle

Grade I pile The pile shaft is integral

Grade II pile There are slight defects in the pile shaft, which will not influence the normal performance of the bearing capacity of the pile shaft structure

Grade III pile There are obvious defects in the pile shaft, which influence the bearing capacity of the pile shaft structure

Grade IV pile There are serious defects in pile shaft



Notes: 1 It is necessary to further determine the degree of influence of the defects in Grade III pile shafts on the bearing capacity of pile shaft structure;



2 Grade IV piles shall be subjected to engineering treatment.



3.7.4 The testing results of the bearing capacity of engineering piles shall include the conclusion whether the bearing capacity of each tested pile meets the design requirements.



3.7.5 If the normal use of the tested pile may be affected after testing, it shall be explained in the testing report.



3.7.6 The testing report shall include accurate conclusions be prepared in standard words. In case of any confusing terms and concepts, the requirements of this code shall prevail.



 

3.7.7 The testing report shall cover:



1 Name of the entrusting party, work name, work location, development organization, investigation organization, design organization, supervision organization, construction organization, foundation type, design requirements, testing purpose, testing basis, testing quantity and testing date;



2 Main geotechnical investigation data;



3 The number, position and related construction records of the test object;



4 Main testing instruments and equipment;



5 Testing methods;



6 Actual measurement and calculation analysis charts and testing data summary results;



7 Description of abnormal conditions during testing (if necessary);



8 Testing conclusions.

 

4 Standard penetration test



4.1 Application scope



4.1.1 The standard penetration test may be used for the following subgrade testings:



1 Estimate the bearing capacity of natural subgrades such as sandy soil, silty soil, cohesive soil and granite residual soil subgrades, and identify their geotechnical properties.



2 Estimate the bearing capacity of non-gravel soil replacement subgrade, dynamic consolidation subgrade, preloaded subgrade, vibroflotation compaction subgrade without additional backfill materials, grouting subgrade and others of treatment soils, and evaluate the subgrade treatment effect.



3 Evaluate the reinforcement construction quality of composite subgrade.



4.1.2 Identification of geotechnical properties of the bearing stratum at tip of cast-in-situ concrete pile by standard penetration test may be carried out with reference to this Clause.



4.2 Equipment



4.2.1 The equipment for standard penetration test shall be in accordance with those specified in Table 4.2.1.



Table 4.2.1 Specifications of equipment for standard penetration test

Drop hammer Hammer mass (kg) 63.5±0.5

Falling distance (cm) 76±2

Penetrometer Split pipe Length (mm) >500

Outer diameter (mm) 51±1

Inner diameter (mm) 35±1

Pipe shoe Length (mm) 50~76

Blade angle (°) 18~20

Thickness of single blade (mm) 2.5

Drill pipe Diameter (mm) 42~50

Relative bending <0.5%



4.2.2 The standard penetration test shall be carried out by the free-fall hammer method with automatic decoupling.



 

4.3 On-site testing



4.3.1 Rotary drilling shall be adopted for standard penetration test holes. When drilling the standard penetration test hole, the water level in the hole shall be kept slightly higher than the groundwater level outside the hole. When the hole wall is unstable, slurry retaining wall may be adopted. The hole shall be drilled to a level 15cm above the test elevation, and then the residual soil at the bottom of hole shall be removed before conducting the test.



4.3.2 The drop hammer height of standard penetration test is 76±2cm, and the blow rate shall be less than 30 blows/min. During the test, the perpendicularity of the penetrator, probe rod and guide rod shall be kept after connection, so as to reduce the friction between the guide rod and hammer and avoid the eccentric hammering and lateral sway.



4.3.3 After the penetrator is driven into the soil for 15cm, start to record the blow count per 10cm of driving depth, and the blow count required for accumulated driving depth of 30cm is the measured blow count of standard penetration test, N′. If the penetration depth is less than 30cm when the blow count has reached 50 blows, the total penetration depth of 50 blows shall be recorded, the measured blow count of standard penetration test, N′, shall be calculated using Formula (4.3.3) and the test shall be terminated.



(4.3.3)



where,



N′——the measured blow count of standard penetration test;



ΔS——the total penetration depth of 50 blows, cm.



Note: When identifying the geotechnical properties of the bearing stratum at tip of cast-in-situ concrete pile, the standard penetration blow count shall reach 100 blows before the test can be terminated.



4.3.4 After the penetrator is pulled out, the soil sample in the penetrator shall be identified and described.



4.3.5 At least three standard penetration tests shall be conducted in each testing hole, the standard penetration test points shall be at equal spacing in the same testing hole, and the depth spacing should be 1.0~1.5m.



When identifying the geotechnical properties of the bearing stratum at tip of cast-in-situ concrete pile, standard penetration test should be conducted within 1m from pile bottom.

 

4.3.6 The standard penetration test data may be recorded in the format of Annex A, Table A.0.1.



4.4 Testing data analysis and judgment



4.4.1 To determine the characteristic value of subgrade bearing capacity, the corrected blow count of standard penetration test, N, should be adopted; to judge liquefaction of sandy soil and silty soil and to distinguish the geotechnical properties of soil, the measured blow count of standard penetration test, N′, should be adopted. When rod length correction is required, the blow count shall be corrected against the probe rod length using Formula (4.4.1).



N=αN′ (4.4.1)



where,



N——the corrected blow count of standard penetration test;



N′——the measured blow count of standard penetration test;



α——the correction coefficient for probe rod length, which may be determined according to Table 4.4.1.



Table 4.4.1 Correction coefficient for probe rod length of standard penetration test

Probe rod length (m) ≤3 6 9 12 15 18 21

α 1.00 0.92 0.86 0.81 0.77 0.73 0.70



4.4.2 For natural soil subgrade and foundation of treatment soils, the standard penetration test results shall provide the relationship curve or chart between the corrected blow count of standard penetration test, N, (or the measured blow count of standard penetration test, N′)/soil stratum classification and the depth of each testing hole. For the reinforcement of composite subgrade, the standard penetration test results shall provide the relationship curve or chart between the corrected blow count of standard penetration test, N, and the depth of each testing hole.



4.4.3 The representative value of standard penetration blow count of each testing hole shall be calculated by the averaging method according to the blow counts of standard penetration test at different depths.

1 General provisions
2 Terms and symbols
2.1 Terms
2.2 Symbols
3 Basic requirements
3.1 General requirements
3.2 Requirements for subgrade testing
3.3 Requirements of testing of foundation pile and foundation anchor
3.4 Requirements for supporting engineering testing
3.5 Requirements for foundation testing and settlement observation
3.6 Verification testing and expanded testing
3.7 Testing result evaluation and testing report
4 Standard penetration test
4.1 Application scope
4.2 Equipment
4.3 On-site testing
4.4 Testing data analysis and judgment
5 Dynamic penetration test
5.1 Application scope
5.2 Equipment
5.3 On-site testing
5.4 Testing data analysis and judgment
6 Cone penetration test
6.1 Application scope
6.2 Instruments and equipment
6.3 On-site testing
6.4 Test data analysis and judgment
7 Vane shear test
7.1 Application scope
7.2 Instruments and equipment
7.3 On-site testing
7.4 Test data analysis and judgment
8 Plate loading test
8.1 Application scope
8.2 Instruments and equipment and their installation
8.3 On-site testing
8.4 Testing data analysis and judgment
9 Low strain integrity testing
9.1 Application scope
9.2 Instruments and equipment
9.3 On-site testing
9.4 Testing data analysis and judgment
10 High strain dynamic testing
10.1 Application scope
10.2 Instruments and equipment
10.3 On-site testing
10.4 Testing data analysis and judgment
11 Cross hole sonic logging
11.1 Application scope
11.2 Instruments and equipment
11.3 Embedding of sonic logging pipe
11.4 On-site testing
11.5 Testing data analysis and judgment
12 Core drilling method
12.1 Application scope
12.2 Equipment
12.3 On-site operation
12.4 Core specimen taking and processing
12.5 Compressive strength test of core specimen
12.6 Testing data analysis and judgment
13 Single-pile vertical compressive static loading test
13.1 Application scope
13.2 Instruments and equipment and their installation
13.3 On-site testing
13.4 Testing data analysis and judgment
14 Single-pile vertical pull-out static loading test
14.1 Application scope
14.2 Instruments and equipment and their installation
14.3 On-site testing
14.4 Testing data analysis and judgment
15 Single-pile horizontal static loading test
15.1 Application scope
15.2 Instruments and equipment and their installation
15.3 On-site testing
15.4 Testing data analysis and judgment
16 Acceptance test of retaining anchor and soil nail
16.1 Application scope
16.2 Instruments and equipment and their installation
16.3 On-site testing
16.4 Testing data analysis and judgment
17 Foundation anchor pull-out test
17.1 Application scope
17.2 Instruments and equipment and their installation
17.3 On-site testing
17.4 Test data analysis and judgment
18 Settlement observation
18.1 Application scope
18.2 Observation grade and instruments and equipment
18.3 Setting of bench mark and observation point
18.4 Site observation
18.5 Data analysis and evaluation
Annex A Testing record form of building foundation
Annex B Statistical calculation method of foundation soil test data
Annex C Correction of the blow count of dynamic penetration test
Annex D Calibration of cone penetration probe
Annex E Treatment of concrete pile head
Annex F Installation of sensors for high strain dynamic testing
Annex G Pile driving test and pile driving monitoring in high strain dynamic testing
G.1 Pile driving test
G.2 Hammer stress monitoring of pile shaft
G.3 Hammer energy monitoring
Annex H Processing and measurement of concrete core specimens
Explanation of wording in this code

1 总 则
1.0.1为提高建筑地基基础检测水平，统一建筑地基基础检测方法，保证工程检测质量，做到安全适用、数据准确、技术先进、经济合理、环境保护，制定本规范。
1.0.2本规范适用于广东省的建筑工程地基基础验收检测。用于其他目的的和其他行业的地基基础检测可参照执行。
1.0.3建筑地基基础检测应综合考虑地质条件、地基基础设计等级、地基基础类型、施工质量可靠性、各种检测方法的特点和适用范围等因素，合理选择检测方法、确定检测数量。
1.0.4建筑地基基础检测除应执行本规范外，尚应符合国家工程建设标准强制性条文。
2术语和符号
2.1术语
2.1.1 地基subgrade，foundation soils
支承基础的土体或岩体。
2.1.2天然地基natural foundation，natural subgrade
在未经人工处理的天然土(岩)层上直接修筑基础的地基。可分为天然土地基和天然岩石地基。
2.1.3处理土地基the foundation of treatment soils
为提高地基的承载力、改善变形性质或渗透性质，对土进行人工处理后的地基。处理土地基包括换填地基、预压处理地基、强夯处理地基、不加填料振冲加密处理地基、注浆地基等。
2.1.4复合地基composite subgrade，composite foundation
部分土体被增强或被置换形成增强体，由增强体和周围地基土共同承担荷载的地基。
2.1.5 基桩foundation pile
桩基础中的单根桩。
2.1.6锚杆anchor
由设置于钻孔内、端部伸入稳定岩土层中的钢筋或钢绞线等抗拉材料与孔内注浆体组成的抗拉构件。
2.1.7支护锚杆retaining anchor
将围护结构所承受的侧向荷载，通过锚杆的拉结作用传递到周围的稳定岩土层中去的锚杆。
2.1.8基础锚杆foundation anchor
将基础承受的向上竖向荷载，通过锚杆的拉结作用传递到基础底部的稳定岩土层中去的锚杆。
2.1.9土层锚杆soil anchor
锚固段设置于土层中的锚杆。
2.1.10岩石锚杆rock anchor
锚固段设置于岩石中的锚杆。
2.1.11 土钉soil nail
用来加固并同时锚固现场原位土体，依靠与土体之间的界面粘结力或摩擦力，在土体发生变形的条件下被动受力，并主要承受拉力作用的细长构件。
2.1.12标准贯入试验standard penetration test(SPT)
用质量为63.5kg的穿心锤，以76cm的落距，将标准规格的贯入器，自钻孔底部预打15cm，记录再打入30cm的锤击数，判定土的物理力学特性的一种原位试验方法。
2.1.13 圆锥动力触探试验dynamic penetration test(DPT)
用标准质最的重锤，以一定高度的自由落距，将标准规格的圆锥形探头贯入土中，根据打入土中一定距离所需的锤击数，判定土的物理力学特性的一种原位试验方法。
2.1.14静力触探试验cone penetration test(CPT)
通过静力将标准圆锥形探头匀速压入土中，根据测定触探头的贯入阻力，判定土的物理力学特性的一种原位试验方法。
2.1.15 十字板剪切试验vane shear test(VST)
用插入土中的标准十字板探头，以一定速率扭转，量测土破坏时的抵抗力矩，测定土的不排水抗剪强度的一种原位试验方法。
2.1.16 平板载荷试验plate loading test(PLT)
对天然地基、处理土地基、复合地基的表面逐级施加竖向压力，测量其沉降随时间的变化，以确定其承载能力的试验方法。
2.1.17低应变法low strain integrity testing
采用低能量瞬态激振方式在桩顶激振，实测桩顶部的速度时程曲线，通过波动理论分析，对桩身完整性进行判定的检测方法。
2.1.18 高应变法high strain dynamic testing
用重锤冲击桩顶，实测桩上部的速度和力时程曲线，通过波动理论分析，对单桩竖向抗压承载力和桩身完整性进行判定的检测方法。
2.1.19声波透射法cross hole sonic logging
在预埋声测管之间发射并接收声波，通过实测声波在混凝土介质中传播的声时、频率和波幅衰减等声学参数的相对变化，对桩身和地下连续墙墙体完整性进行判定的检测方法。
2.1.20钻芯法core drilling method
用钻机钻取复合地基竖向增强体、地下连续墙、混凝土灌注桩及其持力层的芯样，判定其完整性、芯样试件强度、底部沉渣厚度及持力层岩土性状的检测方法。
2.1.21单桩静载试验static loading test
在桩顶部逐级施加竖向压力、竖向上拔力或水平推力，观测桩顶部随时间产生的沉降、上拔位移或水平位移，以确定相应的单桩竖向抗压承载力、单桩竖向抗拔承载力和单桩水平承载力的试验方法。
2.1.22沉降观测settlement observation
测定建(构)筑物的沉降随时间的变化的观测方法。
2.1.23桩身完整性pile integrity
反映桩身截面尺寸相对变化、桩身材料密实性和连续性的综合定性指标。
2.1.24桩身缺陷pile defects
桩身断裂、裂缝、缩径、夹泥(杂物)、空洞、蜂窝、松散等现象的统称。
2.1.25声测线wave measure line
某一检测剖面的两个声测通道中的测点之间的连线。
2.1.26声测线完整性函数值the function value of wave measure line's integrity
依据声测线上接收声波的声参数及波形畸变程度确定的数值，取值范围为1～4，它反映的是该声测线声场辐射区域的桩身混凝土质量。
2.1.27桩身横截面完整性类别指数the exponent of pile cross section's integrity grade
综合横截面上各声测线的完整性函数值而得到的反映该横截面桩身混凝土完整性状况的指标，取值范围为1～4。
2.2符号
2.2.1抗力和材料性能
c——桩身一维纵向应力波传播速度(简称桩身波速)；
Cu——地基土不排水抗剪强度；
E——桩身弹性模量；
E0——地基变形模量；
fak——地基承载力特征值；
fcu——混凝土芯样试件抗压强度；
fa——双桥探头的侧壁摩阻力；
fspk——复合地基承载力特征值；
m——地基土水平抗力系数的比例系数；
N——标准贯入试验修正锤击数；
N′——标准贯入试验实测锤击数
Nk——标准贯入试验锤击数标准值
N10——轻型圆锥动力触探锤击数；
N63.5——重型圆锥动力触探锤击数；
N120——超重型圆锥动力触探锤击数；
Nu——锚杆轴向受拉承载力设计值；
p——地基承载力特征值；
ps——单桥探头的比贯入阻力；
qc——双桥探头的锥头阻力；
Qu——单桩竖向抗压极限承载力；
Ra——单桩竖向抗压承载力特征值；
Rt——锚杆抗拔承载力特征值；
v——桩身混凝土声速；
Z——桩身截面力学阻抗；
μ——土的泊松比；
ρ——桩身质量密度。
2.2.2作用与作用效应
F——锤击力；
H——单桩水平静载试验中作用于桩身的水平力；
Nmax——锚杆的最大试验荷载；
Pf——剪损土体的总作用力；
Q——施加于单桩和地基的竖向压力荷载，施加于锚杆的轴向拉力荷载；
s——沉降量；
U——单桩竖向抗拔静载试验中施加的上拔荷载；
V——质点运动速度；
Y0——单桩水平静载试验中水平力作用平面的桩身水平位移；
δ——单桩竖向抗拔静载试验中的桩顶上拔量、锚头位移。
2.2.3几何参数
A——桩身横截面面积；
b——矩形桩的边宽，承压板直径或边宽；
b0——桩身计算宽度；
B——支墩宽度，支座边宽；
d——桩身直径(管桩外径)，芯样试件的平均直径；
L——桩长。
2.2.4计算系数
Ae——声波透射法波幅异常判断的临界值；
Je——凯司法阻尼系数；
α——修正系数，摩阻比(％)，桩的水平变形系数；
β——高应变法桩身完整性系数；
λ——样本中不同统计个数对应的系数；
vy——桩顶水平位移系数；
ξ——混凝土芯样试件抗压强度换算系数。
2.2.5其他
Ap——声波波幅；
a——声波信号首波峰值电压；
f——频率；
n——样本数量；
T——信号周期；
t——时间；
v0——声速的异常判断值；
v01——异常小值判断值；
v02——异常大值判断值；
vc——声速的异常判断临界值；
vL——桩身混凝土声速低限值；
Δf——频域曲线上相邻峰之间的频率差；
Δt——入射波波峰与反射波波峰之间的时间差。
3基本规定
3.1一般规定
3.1.1 建筑地基基础工程验收应按本规范的规定进行质量检测。
3.1.2建筑地基基础工程检测分为地基检测、基桩及基础锚杆检测、支护工程检测和基础检测。应根据检测目的合理选择检测方法。
1地基检测。地基检测内容包括天然地基承载力、变形参数及岩土性状评价，处理土地基承载力、变形参数及施工质量评价，复合地基承载力、变形参数及复合地基增强体的施工质量评价。检测方法可选择平板载荷试验、钻芯法、标准贯入试验、圆锥动力触探试验、静力触探试验、十字板剪切试验、土工试验、低应变法、深层平板载荷试验和岩基载荷试验。
2基桩及基础锚杆检测。基桩及基础锚杆检测内容包括工程桩的桩身完整性和承载力检测、基础锚杆抗拔承载力检测。桩身完整性检测可选择钻芯法、声波透射法、高应变法和低应变法等。单桩竖向抗压承载力检测可选择单桩竖向抗压静载试验和高应变法，单桩竖向抗拔承载力检测可采用单桩竖向抗拔静载试验，单桩水平承载力检测可采用单桩水平静载试验，基础锚杆抗拔承载力检测可采用基础锚杆抗拔试验。
3支护工程检测。支护工程检测内容包括土钉和支护锚杆抗拔力检测、土钉墙施工质量检测、水泥土墙墙身完整性检测、地下连续墙墙体质量检测、逆作拱墙的施工质量检测、用于支护的混凝土灌注桩的桩身完整性检测。检测方法可选择土钉和支护锚杆验收试验、钻芯法、声波透射法和低应变法。
4 基础检测。基础检测内容包括各类基础及桩基础承台的施工质量检测和建筑物沉降观测。混凝土强度可选择结构钻芯法和回弹法。
3.1.3检测工作的程序，应按图3.1.3进行。

接受委托
调查、资料收集
制定检测方案
检测试验前准备
现场检测
数据分析和结果评价
检测报告
仪器设备较准、率定
重新检测
必要时
验证检测、扩大检测
必要时
图3.1.3检测工作程序框图
3.1.4调查、资料收集宜包括下列内容：
1 收集被检测工程的岩土工程勘察资料、地基基础设计及施工资料；了解施工工艺和施工中出现的异常情况。
2进一步明确委托方的具体要求。
3分析检测项目现场实施的可行性。
3.1.5检测单位应根据调查结果和确定的检测目的，选择检测方法，制定检测方案。检测方案宜包含以下内容：工程概况，检测方法及其所依据的规范标准，检测数量，抽样方案。所需的机械设备和人工配合、试验时间要求，必要时还应包括桩头开挖、加固、处理，场地平整，道路修筑，供水供电等要求。
当根据现场试验结果，判断所选择的检测方法不能满足检测目的时，应重新选择检测方法，制定检测方案。不能完全满足检测目的的检测结果，不能计入抽检数量。
3.1.6地基基础工程验收检测的抽检数量应按单位工程计算。当单位工程由若干个子单位工程组成时，抽检数量宜按子单位工程计算。
同一单位工程采用不同地基基础类型时，应分别确定检测方法和抽检数量；同一单位工程中采用不同桩型或不同地基处理方法的，宜分别确定检测方法和抽检数量。
小区工程中，地基基础设计等级为丙级，且各单位工程的工程桩总数少于30根或地基处理面积小于300 m2，经工程质量各方责任主体共同确认，可将地质条件相近、施工工艺相同的若干个单位工程合并起来确定抽检数量，但应对每单位工程进行承载力抽检，承载力检测抽检数量：当采用单桩静载试验时不得少于1根、当采用高应变法时不得少于2根、当采用平板载荷试验时不得少于2点。
对地基处理面积超过20000m2或工程桩总数超过2000根的大型单位工程，超过部分的抽检数量可适当减少，但不应少于相应规定抽检数量的50％。
对补桩、加固处理后的桩应进行抽检。
3.1.7当发现检测数据异常或对检测结果有怀疑时，应查找原因，必要时应重新检测。标准贯入试验、静力触探试验，圆锥动力触探试验、十字板剪切试验可在原试验孔附近重新选点进行试验，低应变法、高应变法、声波透射法可在原受检桩上重新进行检测。
3.1.8检测用计量器具应进行校准。仪器设备性能应符合相应检测方法的技术要求。
仪器设备使用时应按校准结果设置相关参数。
检测前应对仪器设备检查调试，检测过程中应加强仪器设备检查，必要时在检测前和检测过程中应对仪器进行率定。
3.1.9现场检测期间。除应执行本规范的有关规定外，还应遵守国家有关安全生产的规定；当现场操作环境不符合仪器设备使用要求时，应采取有效的措施。保证仪器设备的正常工作。
3.2地基检测规定
3.2.1天然土地基、处理土地基和复合地基应合理选择两种或两种以上的检测方法进行地基检测。并应符合先简后繁、先粗后细、先面后点的原则。
3.2.2处理土地基和复合地基检测宜在合理间歇时间后进行。
3.2.3地基检测抽检位置应按下列情况综合确定：
1施工出现异常情况的部位；
2设计认为重要的部位；
3局部岩土特性复杂可能影响施工质量的部位；
4 当采取两种或两种以上检测方法时，应根据前一种方法的检测结果确定后一种方法的抽检位置；
5同类地基的抽检位置宜均匀分布。
3.2.4天然岩石地基应采用钻芯法进行抽检，单位工程抽检数量不得少于6个孔，钻孔深度应满足设计要求，每孔芯样截取一组三个芯样试件。天然岩石地基特性复杂的工程应增加抽样孔数。当岩石芯样无法制作成芯样试件时，应进行岩基载荷试验，对强风化岩、全风化岩宜采用平板载荷试验，试验点数不应少于3点。
3.2.5天然土地基、处理土地基应进行平板载荷试验，单位工程抽检数量为每500m2不应少于1个点，且不得少于3点，对于复杂场地或重要建筑地基应增加抽检数量。
3.2.6天然土地基、处理土地基在进行平板载荷试验前，应根据地基类型选择标准贯入试验、圆锥动力触探试验、静力触探试验、十字板剪切试验等一种或一种以上的方法对地基处理质量或天然地基土性状进行普查，单位工程抽检数量为每200 m2不应少于1个孔，且不得少于10孔，每个独立柱基不得少于1孔，基槽每20延米不得少于1孔。检测深度应满足设计要求。
当无工程实践经验时，检测可按下列规定进行：
1天然地基基槽(坑)开挖后，可选择标准贯入试验、圆锥动力触探试验、静力触探试验或其他方法对基槽(坑)进行检测。
2换填地基(含灰土地基、砂和砂石地基、土工合成材料地基、粉煤灰地基)可采用圆锥动力触探试验或标准贯入试验进行检测。
换填地基必须分层进行压实系数检测，压实系数可选择《土工试验方法标准》GB/T 50123中的环刀法、灌砂法、灌水法或其他方法进行检测，抽检数量：对大基坑每50～100m2面积内不得少于1个检测点；对基槽每10～20m不得少于1个检测点；每个独立柱基不得少于1个检测点。
3预压地基可选择十字板剪切试验和室内土工试验进行检测。
4强夯处理地蕈可选择原位测试和室内土工试验进行检测。
5不加填料振冲加密处理地基可选择动力触探、标准贯入试验或其他方法进行检测。
6注浆地基可选择标准贯入试验、钻芯法进行检测。
3.2.7复合地基及强夯置换墩应进行复合地基平板载荷试验，单位工程抽检平板载荷试验点数量位为总桩(墩)数的0.5％～1％，且不得少于3点。同一单位工程复合地基平板载荷试验形式可选择多桩复合地基平板载荷试验或单桩(墩)复合地基平板载荷试验，也可一部分试验点选择多桩复合地基平板载荷试验而另一部分试验点选择单桩复合地基平板载荷试验。
3.2.8复合地基及强夯置换墩在进行平板载荷试验前，应采用合适的检测方法对复合地基的桩体施工质量进行检测，抽检数量：当采用标准贯入试验、圆锥动力触探试验等方法时，单位工程抽检数量应为总桩(墩)数的0.5％～1％，且不得少于3根；当采用单桩竖向抗压载荷试验、钻芯法时，抽检数量不应少于总桩数的0.5％，且不得少于3根。检测方法和抽检数量还应符合下列规定：
1水泥土搅拌桩和竖向承载旋喷桩应进行单桩竖向抗压载荷试验；
2水泥土搅拌桩和高压喷射注浆加固体的施工质量应采用钻芯法进行检测；
3水泥粉煤灰碎石桩应采用低应变法或钻芯法进行桩身完整性检测，低应变法的抽检数量不应少于总桩数的10％；
4振冲桩桩体质量应采用圆锥动力触探试验或单桩载荷试验等方法进行检测。对碎石桩桩体质量检测，应采用重型动力触探试验；
5砂石桩桩体质量应采用圆锥动力触探试验等方法进行检测。砂石桩宜进行单桩载荷试验；
6强夯置换地基应采用圆锥动力触探等方法进行检测。
3.2.9 当设计有要求时，应对复合地基桩间土和强夯置换墩墩间土进行抽检，检测方法和抽检数量宜参照本规范第3.2.5条和第3.2.6条的规定。
3.3基桩及基础锚杆检测规定
3.3.1工程桩验收应进行桩身完整性检测和单桩承载力检测。
宜先进行桩身完整性检测，后进行承载力检测；当基础埋深较大时，桩身完整性检测宜在基坑开挖至基底标高后进行。
3.3.2从成桩到开始试验的间歇时间应符合下列规定：
1 当采用低应变法或声波透射法检测时，受检桩桩身混凝土强度不得低于设计强度等级的70％或预留立方体试块强度不得小于15MPa。
2当采用钻芯法检测时，受检桩的混凝土龄期不得小于28d或预留立方体试块强度不得低于设计强度等级。
3高应变法和静载试验的间歇时间：混凝土灌注桩的混凝土龄期不得小于28d。预制桩(钢桩)在施工成桩后，对于砂土。不宜少于7d；对于粉土，不宜少于10d；对于非饱和黏性土.不宜少于15d；对于饱和黏性土，不宜少于25d；对于桩端持力层为遇水易软化的风化岩层，不应少于25d。
3.3.3桩身完整性和单桩承载力抽样检测的受检桩宜按下列情况综合确定：
1施工质量有疑问的桩；
2设计认为重要的桩；
3局部地质条件出现异常的桩；
4当采用两种或两种以上检测方法时，宜根据前一种检测方法的检测结果来确定后一种检测方法的受检桩；
5同类型桩宜均匀分布。
3.3.4混凝土灌注桩的桩身完整性检测的抽检数量应符合下列规定：
1 柱下三桩或三桩以下的承台。每个承台抽检桩数不得少于1根。
2当满足下列条件之一时，柱下四桩或四桩以上承台抽检桩数不应少于相应总桩数的30％，且单位工程抽检总桩数不得少于20根。
1)地基基础设计等级为甲级的桩基工程：
2)场地地质条件复杂的桩基工程；
3)施工工艺导致施工质量可靠性低的桩基工程；
4)本地区采用的新桩型或采用新工艺施工的桩基工程。
对于其他工程，柱下四桩或四桩以上承台抽检桩数不应少于相应总桩数的20％，且单位工程抽检总桩数不得少于10根。
3对于直径大于等于800mm的端承型混凝土灌注桩，应在上述两款规定的抽检桩数范围内，选用钻芯法或声波透射法对部分受检桩进行桩身完整性检测，抽检数量不应少于总桩数的10％。
4 当检测数据难以评价整根受检桩的桩身质量，不能确定桩身完整性类别时，不得计入上述三款规定的抽检桩数范围内，应重新确定受检桩或重新选择检测方法，以确保抽检桩数满足本条的规定要求。
3.3.5混凝土灌注桩的单桩竖向抗压承载力检测应符合下列规定：
1采用静载试验时，抽检数量不应少于总桩数的1％，且不得少于3根；当总桩数在50根以内时，不得少于2根。采用高应变法时，抽检数量不应少于总桩数的5％，且不得少于5根。
2下列条件之一时，应采用静载试验进行单桩竖向抗压承载力检测：
1)地基基础设计等级为甲级的桩基工程；
2)场地地质条件复杂的桩基工程；
3)施工工艺导致施工质量可靠性低的桩基工程；
4)桩身有明显缺陷，对桩身结构承载力有影响，采用完整性检测方法难以确定其影响程度；
5)本地区采用的新桩型或采用新工艺施工的桩基工程。
3对于直径大于等于1500mm的端承型混凝土灌注桩，经工程质量各方责任主体共同确认。因试验设备或现场条件限制，难以进行单桩竖向抗压承载力检测时，应进行桩身完整性检测和桩端持力层鉴别。检测方法应选择钻芯法、声波透射法、高应变法。总抽检桩数应符合本规范3.3.4条的规定，其中，钻芯法的抽检桩数不应少于总桩数的10％，且不得少于10根。若成桩前已进行岩基载荷试验(不少于3个点)，总抽检桩数可减少2个百分点。
3.3.6预制桩桩身完整性和单桩竖向抗压承载力检测应符合下列规定：
1条件允许时。宜采用孔内摄像或将低压灯泡放入管桩内腔对桩身完整性进行检查。
2符合下列条件之一的预制桩工程。应采用低应变法进行桩身完整性检测和静载试验进行单桩竖向抗压承载力检测，完整性检测数量不应少于总桩数的20％，静载试验抽检数量不少于总桩数的1％，且不少于3根，当总桩数在50根以内时，不得少于2根。
1)场地地质条件为岩溶的桩基工程；
2)非岩溶地区上覆土层为淤泥等软弱土层，其下直接为中风化岩、或微风化岩、或中风化岩面上只有较薄的强风化岩；
3)桩端持力层为遇水易软化的风化岩层；
4)采用“引孔法”施工的桩基工程。
3对本条第2款规定以外的预制桩工程，应采用高应变法同时进行桩身完整性检测和单桩竖向抗压承载力检测，抽检桩数不应少于同条件下总桩数的8％，且不得少于10根。地基基础设计等级为甲级和地质条件较为复杂的乙级管桩基础工程，抽检桩数应增加一个百分点。其中符合下列条件之一的桩基工程，抽检桩数可减少一个百分点；
1)已按有关规范的规定对焊接接缝进行了抽检的桩基工程；
2)对于已采用孔内摄像或低压灯泡进行桩身完整性检查、检查桩数超过工程桩总数的80％且未发现明显质量缺陷的预应力管桩工程；
3)采用机械接头的预应力管桩工程；
4)施工过程中采用打桩自动记录设备进行施工记录的桩基工程。
注：当不采用高应变法进行抽检时，检测方法和抽检桩数应符合本条第2款的规定。
3.3.7钢桩应采用高应变法和静载试验进行检测。高应变法抽检数量不应少于总桩数的5％，且不得少于10根；静载试验抽检数量不应少于总桩数的0.5％，且不得少于3根，当总桩数在50根以内时，不得少于2根。
3.3.8采用高应变法进行打桩过程监测的工程桩或施工前进行静载试验的试验桩，如果试验桩施工工艺与工程桩施工工艺相同，桩身未破坏且单桩竖向抗压承载力大于等于2倍单桩竖向抗压承载力特征值。这类试验桩的桩数的一半可计入同方法验收抽检数量。
3.3.9对竖向抗拔承载力有设计要求的桩基工程，应进行单桩竖向抗拔静载试验。抽检桩数不应少于总桩数的1％，且不得少于3根。
3.3.10对水平承载力有设计要求的桩基工程，应进行单桩水平荷载静载试验。抽检桩数不应少于总桩数的1％，且不得少于3根。
3.3.11基础锚杆应进行抗拔试验，抽检数量不应少于锚杆总数的5％。且不得少于6根。
3.4支护工程检测规定
3.4.1 支护锚杆应进行验收试验，抽检数量不应少于锚杆总数的5％，且不得少于6根。
3.4.2土钉墙质量验收应进行土钉抗拔力试验，抽检数量应为土钉总数的0.5％～1％，且不得少于10根。墙面喷射混凝土厚度应进行检测，检测方法可采用钻孔法，抽检数量宜每100m2墙面积一组，每组不少于3点。
3.4.3用于支护的混凝土灌注桩应进行桩身完整性检测，抽检数量不宜少于总桩数的10％，且不得少于10根，检测方法可采用低应变法；当根据低应变法检测结果判定的桩身缺陷可能影响桩的水平承载力时，应采用钻芯法补充检测，抽检数量不宜少于总桩数的2％。且不得少于3根。
3.4.4应采用钻芯法对水泥土墙的墙身完整性进行检测，抽检数量不宜少于总桩数的1％，且不得少于5根，并应截取芯样进行抗压强度试验。
3.4.5地下连续墙墙体完整性应选择声波透射法、钻芯法检测。当地下连续墙作为永久性结构的一部分时，抽检数量不应少于总槽段数的20％，且不得少于3个槽段；当地下连续墙作为临时性结构时，抽检数量不应少于总槽段数的10％，且不得少于3个槽段。
3.4.6应对逆作拱墙的施工质量进行检测，抽检数量为每100m2墙面一组，每组不应少于3点，检测方法可采用结构钻芯法。
3.5基础检测和沉降观测规定
3.5.1扩展基础、柱下条形基础、筏形基础和桩基础承台应进行混凝土强度检测，单位工程抽检数量不应少于构件总数的10％。且不应少于3个构件。检测方法可选择钻芯法和同弹法；采用钻芯法检测时，每个构件钻取芯样孔不应少于3个，每孔截取1个芯样试件，对于截面尺寸较小的构件不应少于2个孔。
3.5.2钢筋混凝土基础和桩基础承台宜进行保护层厚度检测，单位工程抽检数量不宜少于构件总数的10％。
3.5.3下列建筑物应进行沉降观测直至沉降达到稳定标准：
1地基基础设计等级为甲级的建筑物；
2复合地基或软弱地基上的地基基础设计等级为乙级的建筑物；
3基础有严重质量问题并经工程处理的建筑物；
4受施工影响的邻近建筑物；
5 受场地地下水等环境因素变化影响的建筑物；
6改扩建工程和加层工程；
7采取新型基础或新型结构的建筑物；
8设计要求进行沉降观测的建筑物。
3.6验证与扩大检测
3.6.1 当对检测结果有异议时，应在原试验点附近重新选点进行试验或在原受检桩上进行验证检测，验证检测的抽检数量宜根据实际情况确定。验证检测应符合下列规定：
1 可根据平板载荷试验结果，综合分析评价标准贯入试验、静力触探试验、圆锥动力触探试验、十字板剪切试验等地基承载力检测结果；
2桩身浅部缺陷可采用开挖验证；
3 桩身或接头存在缺陷的预制桩可采用高应变法进行验证。必要时应进行水平荷载试验或竖向抗拔静载试验；
4可采用钻芯法、高应变法验证低应变法检测结果；
5对于声波透射法检测结果有异议时，可重新组织声波透射法检测，或在同一基桩进行钻芯法验证；
6可在同一基桩增加钻孔验证钻芯法检测结果；
7可采用单桩竖向抗压静载试验验证高应变法单桩承载力检测结果。
3.6.2当检测结果不满足设计要求时，应进行扩大抽检。扩大抽检应采用原抽检用的检测方法或准确度更高的检测方法。当因未埋设声测管而无法采用声波透射法扩大检测时，应采用钻芯法。扩大抽检的数量宜按不满足设计要求的桩数加倍扩大抽检：
1 当平板载荷试验、锚杆及土钉试验、单桩承载力检测或钻芯法抽检结果不满足设计要求时，应按不满足设计要求的数量加倍扩大抽检。
2当采用低应变法抽检桩身完整性所发现的Ⅲ、Ⅳ类桩之和大于抽检桩数的20％时，应按原抽检比例扩大抽检，当两次抽检的Ⅲ、Ⅳ类桩之和仍大于抽检桩数的20％时，该批桩应全数检测。当Ⅲ、Ⅳ类桩之和不大于抽检桩数的20％时，应研究确定处理方案或扩大抽检的方法和数量。
3 当采用高应变法和声波透射法抽检桩身完整性所发现的Ⅲ、Ⅳ类桩之和大干抽检桩数的20％时，应按原抽检比例扩大抽检。当Ⅲ、Ⅳ类桩之和不大于抽检桩数的20％时，应研究确定处理方案或扩大抽检的方法和数量。
4标准贯入试验、圆锥动力触探试验、静力触探试验、十字板剪切试验等方法-抽检孔数超过30％不满足设计要求时，应按不满足设计要求的孔数加倍扩大抽检，或适当增加平板载荷试验数量。
5 当扩展基础、柱下条形基础、筏形基础和桩基础承台的混凝土强度检测结果不满足设计要求时，应按不满足设计要求的数量加倍扩大抽检。检测方法宜采用钻芯法。
注：1 当预制桩检测结果不满足设计要求时，可采用全部复打或复压。然后重新按照本规范第3.5节的规定进行抽检；
2当检测结果满足修改后的设计要求时，可以不进行扩大抽检。
3.6.3验证检测和首次扩大抽检后，应根据检测结果，由监理单位或建设单位会同检测、勘察、设计、施工单位共同研究确定处理方案或进一步抽检的方法和数量。
当对检测结果有怀疑或有争议但又不具备重新检测和验证检测条件时，应由监理单位或建设单位会同检测、勘察、设计、施工单位共同研究确定处理方案。
3.7检测结果评价和检测报告
3.7.1标准贯入试验、静力触探试验、圆锥动力触探试验和十字板剪切试验应给出每个试验孔的检测结果和单位工程的主要土层的评价结果。
3.7.2平板载荷试验应给出每个点的承载力特征值和单位工程的地基承载力特征值，并给出单位工程的地基承载力特征值是否满足设计要求的结论。
3.7.3桩身完整性检测结果应给出每根受检桩的桩身完整性类别。桩身完整性分类应符合表3.7.3的规定，并按本规范第9～12章分别规定的技术内容划分。
表3.7.3桩身完整性分类表
桩身完整性类别 分类原则
I类桩 桩身完整
Ⅱ类桩 桩身有轻微缺陷，不会影响桩身结构承载力的正常发挥
Ⅲ类桩 桩身有明显缺陷，对桩身结构承载力有影响
Ⅳ类桩 桩身存在严重缺陷

注：1应进一步确定Ⅲ类桩桩身缺陷对桩身结构承载力的影响程度；
2 Ⅳ类桩应进行工程处理。
3.7.4工程桩承载力检测结果应给出每根受检桩的承载力是否满足设计要求的结论。
3.7.5受检桩检测后可能影响该桩的正常使用时，应在检测报告中予以说明。
3.7.6检测报告应结论准确、用词规范，对容易混淆的术语和概念应以本规范为准。
3.7.7检测报告应包含以下内容：
1委托方名称，工程名称，工程地点，建设、勘察、设计、监理和施工单位，基础类型，设计要求，检测目的，检测依据，检测数量，检测日期；
2主要岩土工程勘察资料；
3检测对象的编号、位置和相关施工记录；
4主要检测仪器设备；
5检测方法；
6实测与计算分析图表和检测数据汇总结果；
7检测过程中的异常情况描述(必要时)；
8检测结论。
4标准贯入试验
4.1适用范围
4.1.1 标准贯入试验可用于以下地基检测：
1推定砂土、粉土、黏性土、花岗岩残积土等天然地基的地基承载力，鉴别其岩土性状。
2推定非碎石土换填地基、强夯地基、预压地基、不加填料振冲加密处理地基、注浆处理地基等处理土地基的地基承载力，评价其地基处理效果。
3评价复合地基增强体的施工质量。
4.1.2标准贯入试验鉴别混凝土灌注桩桩端持力层岩土性状可参照本章执行。
4.2设备
4.2.1标准贯入试验的设备应符合表4.2.1的规定。
表4.2.1标准贯入试验设备规格
落锤 锤的质量(kg) 63.5±0.5
落 距(cm) 76±2
贯入器 对开管 长 度(mm) >500
外 径(mm) 51±1
内 径(mm) 35±1
管靴 长 度(mm) 50～76
刃口角度(°) 18～20
刃口单刃厚度(mm) 2.5
钻杆 直 径(mm) 42～50
相对弯曲 <0.5％

4.2.2应采用自动脱钩的自由落锤法进行标准贯入试验。
4.3现场检测
4.3.1标准贯入试验孔应采用回转钻进。标准贯入试验孔钻进时。应保持孔内水位略高于孔外地下水位。当孔壁不稳定时，可用泥浆护壁。钻至试验标高以上15cm处，清除孔底残土后再进行试验。
4.3.2标准贯入试验落锤高度为76±2cm，锤击速率应小于30击/min。试验时，应保持贯入器、探杆、导向杆连接后的垂直度，减小导向杆与锤间的摩阻力，避免锤击偏心和侧向晃动。
4.3.3贯入器打入土中15cm后，开始记录每打入10cm的锤击数。累计打入30cm的锤击数为标准贯入试验实测锤击数N′。当锤击数已达50击，而贯入深度未达30cm时，应记录50击的总贯入深度，按式(4.3.3)计算标准贯入试验实测锤击数N′，并终止试验。
(4.3.3)
式中 N′——标准贯入试验实测锤击数；
ΔS—50击的总贯入深度(cm)。
注：当鉴别混凝土灌注桩桩端持力层岩土性状时，标准贯入锤击数应达100击方可终止试验。
4.3.4贯入器拔出后，应对贯入器中的土样进行鉴别描述。
4.3.5每个检测孔的标准贯入试验次数不应少于3次，同一检测孔的标准贯入试验点间距宜为等间距，深度间距宜为1.0～1.5m。
当鉴别混凝土灌注桩桩端持力层岩土性状时，宜在距桩底1m内进行标准贯入试验。
4.3.6标准贯入试验数据可按附录A附表A.0.1的格式进行记录。
4.4检测数据分析与判定
4.4.1 当确定地基承载力特征值时宜采用经过修正的标准贯入试验锤击数N，当判别砂土、粉土液化和鉴别土的岩土性状时宜采用标准贯入试验实测锤击数N′。当须作杆长修正时，锤击数应按式(4.4.1)进行钻杆长度修正。
N=αN′ (4.4.1)
式中 N——标准贯入试验修正锤击数；
N′——标准贯入试验实测锤击数；
α——触探杆长度修正系数，可按表4.4.1确定。
表4.4.1 标准贯入试验触探杆长度修正系数
触探杆长度(m)
α ≤3 6 9 12 15 18 21
1.00 0.92 0.86 0.81 0.77 0.73 0.70

4.4.2对于天然土地基和处理土地基，标准贯入试验结果应提供每个检测孔的标准贯入试验修正锤击数N(或标准贯入试验实测锤击数N′)及土层分类与深度的关系曲线或表格。对于复合地基增强体，标准贯入试验结果应提供每个检测孔的标准贯入试验修正锤击数N与深度的关系曲线或表格。
4.4.3应根据不同深度的标准贯入试验锤击数，采用平均值法计算每个检测孔的标准贯入锤击数代表值。
4.4.4单位工程同一土层的标准贯入锤击数标准值Nk，应根据各检测孔的同一土层的标准贯入试验锤击数平均值按附录B的计算方法确定。统计同一上层标准贯入试验锤击数平均值时，应剔除异常值。
4.4.5砂土、粉土、黏性土、花岗岩残积土等岩土性状可根据标准贯入试验实测锤击数标准值按下列规定进行评价：
1 砂土的密实度可按表4.4.5—1分为松散、稍密、中密、密实。
表4.4.5—1砂土的密实度分类
标准贯入试验锤击数N′
N′≤10 密实度
松散
1030 密实

2粉土的密实度可按表4.4.5—2分为松散、稍密、中密、密实。
表4.4.5—2粉土的密实度分类
标准贯入试验锤击数N′ 密实度
N′≤5 松散
515 密实

3黏性土的状态可按表4.4.5—3分为流塑、软塑、可塑、硬塑、坚硬。
表4.4.5—3黏性土的状态分类
标准贯入试验锤击数N′ 状态
N′≤2 流塑
235 坚硬

4花岗岩类岩石的风化程度可按表4.4.5—4确定。风化软岩可参照执行。
表4.4.5—4花岗岩类岩石的风化程度
标准贯入试验锤击数N′ 风化程度
N′<30 残积土
30≤N′<50 全风化
N′≥50 强风化

5 桩端持力层岩土性状的判别可参照本条第1～4款执行。
4.4.6砂上、粉土、黏性土、花岗岩残积土等地基土承载力特征值可根据标准贯入试验修正锤击数标准值Nk参照表4.4.6-1～表4.4.6-4进行推定。
表4.4.6-1砂土承载力特征值fak(kPa)
Nk土的名称 10 20 30 50
中砂、粗砂 180 250 340 500
粉砂、细秒 140 180 250 340

表4.4.6—2粉土承载力特征值fak(kPa)
Nk 3 4 5 6 7 8 9 10 11 12 13 14 15
fak 105 125 145 165 185 205 225 245 265 285 305 325 345

表4.4.6-3黏性土承载力特征值fak(kPa)
Nk 3 5 7 9 11 13 15 17 19 21 23
fak 105 145 190 235 280 325 370 430 515 600 680

表4.4.6-4花岗岩残积土(全风化岩)
承载力特征值fak(kPa)
Nk 3 5 7 9 11 13 15 17 19 21 23
fak 100 150 200 240 280 320 360 420 500 580 660

4.4.7处理土地基的地基处理效果宜根据检测孔的标准贯入锤击数代表值、同一土层的标准贯入试验锤击数标准值作出相应的评价：
1 非碎石土换土垫层(粉质黏土、灰土、粉煤灰和砂垫层)的施工质量(密实度、均匀性)。
2强夯地基、预压地基、不加填料振冲加密处理地基、注浆地基等处理土地基的均匀性；有条件时，可结合处理前的相关数据评价地基处理有效深度。
3判定处理后的砂土、粉土液化应按照《建筑抗震设计规范》GB 50011—2001执行。
4.4.8非碎石土换填地基、预压处理地基、强夯处理地基、不加料振冲加密处理地基等处理土地基可参照本规范第4.4.6条推定地基承载力和本规范第4.4.5条判断岩土性状。
4.4.9复合地基增强体的施工质量宜根据单桩检测孔的标准贯入锤击数代表值作出相应的评价，评价内容可包括桩身强度和均匀性。
4.4.10检测报告除应包括本规范第3.7.7条内容外，还应包括下列内容：
1标准贯入锤击数及土层分类与深度关系曲线；
2每个检测孔的标准贯入锤击数代表值；
3 同一土层或同一深度范围的标准贯入锤击数标准值；
4岩土性状分析或地基处理效果评价；
5.对地基(土)检测时，提供地基(土)承载力特征值。
5圆锥动力触探试验
5.1适用范围
5.1.1 圆锥动力触探试验可用于推定天然地基的地基承载力，鉴别其岩土性状；推定处理土地基的地基承载力，评价其地基处理效果；检验复合地基增强体的桩体成桩质量；评价强夯置换墩着底情况；鉴别混凝土灌注桩桩端持力层岩土性状。
5.1.2 圆锥动力触探试验的类型有轻型、重型和超重型三种。应根据地质条件合理选择圆锥动力触探试验类型。
5.1.3轻型动力触探试验可用于推定换填地基、黏性土、粉土、粉砂、细砂及其处理土地基的地基土承载力，鉴别地基土性状，评价处理土地基的施工效果。重型动力触探试验可用于推定黏性土、粉土、砂土、中密以下的碎石土及其处理土地基以及极软岩的地基土承载力，鉴别地基土岩土性状，评价处理土地基的施工效果；也可用于检验振冲桩、砂石桩的成桩质量。超重型动力触探试验可用于推定密实碎石土、极软岩和软岩等地基承载力。