标准编号:	SL 253-2018
中文名称:	溢洪道设计规范
英文名称:	Design specification for spillway
行业分类:	SL    水利行业标准
发布机构:	水利部
发布日期:	2018-07-17
实施日期:	2018-10-17
标准状态:	现行
替代旧标准:	SL 253-2000 溢洪道设计规范
翻译语言:	英文
文件格式:	PDF
中文字符数:	80000 字
翻译价格(元):	8400.00 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.



Design specification for spillway (SL 253-2000) is revised in accordance with the arrangement of development and revision plan of water conservancy technical standard and the requirements of SL 1-2014 Specification for the drafting of technical standards of water resources.



The specification consists of 7 clauses and 2 annexes.



——Spillway layout.



——Hydraulic design.



——Structure design.



——Design of foundation and side slope treatment.



——Safety monitoring design.



The main contents revised in this time are as follows:



——The “jet-flow atomization and anti-icing design” is added.



——The proposal of “main and auxiliary spillways" is deleted.



——The design contents of "ski jump spillway" and "free overflow tunnel spillway" are added.



——The types and design contents of step, narrow slit and energy dissipation by hydraulic jump with step-down floor are supplemented.



——The design flood standard for energy dissipation and scour prevention structures of spillway is not repeated and revised to be determined in accordance with the relevant provisions of SL 252 Standard for classification and flood control of water resources and hydroelectric project.



——The relevant provisions of spillway structural design are revised and the material physical and mechanical parameter table is canceled in accordance with the relevant provisions of SL 191-2008 Design code for hydraulic concrete structures.



——The Annex B “Anti-sliding stability and anti-shearing parameters of weir (sluice) foundation and weir body” in the former specification is canceled.



——The relationship is coordinated of the spillway load calculation, retaining wall design, side slope design and safety monitoring design to their corresponding special specifications, and Annex C “Load calculation formula”, Annex D “Side slope rock mass stability classification and treatment measures” and Annex E “Hydraulic monitoring design requirements” in the former specification are canceled.



The mandatory provisions in this specification are items 1-4 in 3.3.9, item 3 in 5.3.9 and 5.3.13 and marked in bold and must be strictly implemented.



The previous editions of this specification are as follows:



——SDJ 341-89;



——SL 253-2000.



During the implementation of this standard, all organizations are kindly asked to pay attention to summing up experience, accumulating data and feeding relevant opinions and suggestions back to Ministry of Water Resources, Department of International Cooperation, Science Technology at any time (correspondence address: No.2, 2nd Lane, Baiguang Road, Xicheng District, Beijing; Postal code: 100053; Tel.: 0086-(0)10-63204533; E-mail: bzh@mwr.gov.cn) for reference in future revisions.







Design specification for spillway



1 General provisions



1.0.1 This specification is formulated in order to regulate the spillway design and achieve safety and reliability, rational economy, advanced technology, environmental coordination and convenient management and operation.



1.0.2 This specification is applicable to the design of Classes 1, 2 and 3 spillways (including ski jump spillways and free overflow tunnel spillways) on rock foundations in large- and medium-sized water conservancy and hydropower projects. Reference may be made to this specification for the design of Classes 4 and 5 spillways.



1.0.3 Flood standard for spillway (including that for energy dissipation and scour prevention structures of spillway) shall be determined in accordance with the class of spillway and the provisions of SL 252 Standard for classification and flood control of water resources and hydroelectric project.



1.0.4 For spillways of large-sized projects or medium-sized projects with complicated hydraulic conditions, the rationality of project layout and hydraulic design shall be demonstrated based on hydraulic model tests.



1.0.5 For spillway design, the spillway operation and gate opening and closing mode shall be determined according to the flood control dispatching requirements of the project.



1.0.6 This standard mainly cites the following standards:



GB/T 50662 Code for design of hydraulic structures against ice and freezing action

GB 51247 Code for seismic design of hydraulic structures

SL 74 Hydraulic and hydroelectric engineering specification for design of steel gate

SL 191 Design code for hydraulic concrete structures

SL 252 Standard for classification and flood control of water resources and hydroelectric project

SL 265 Design specification for sluice

SL 279 Specification for design of hydraulic tunnel

SL 319 Design specification for concrete gravity dams

SL 379 Design specification for hydraulic retaining wall

SL 386 Design code for engineered slopes in water resources and hydropower projects

SL 486 Technical specification for strong vibration safety monitoring of hydraulic structures

SL 616 Specification for hydraulic prototype observation of water conservancy and hydropower projects

SL 654 Specification for design of reasonable service life and durability of water conservancy and hydropower projects

SL 725 Design specification for safety monitoring in water and hydropower projects

SL 744 Design specification for load of hydraulic structures

DL/T 5207 Technical specification for abrasion and cavitation resistance of concrete in hydraulic structures



1.0.7 In addition to this standard, the design of spillways shall also comply with those specified in the current relevant standards of the nation.



2 Terms



2.0.1



main spillway



spillway that is used either alone or in combination with other outlet structures and whose discharge capacity meets the design flood standard requirements



2.0.2



emergency spillway



spillway for discharging abnormal flood exceeding the design flood standard



2.0.3



free overflow spillway



spillway with the inlet control section open and with the discharged water having free surface



2.0.4



normal channel spillway



free overflow spillway with the chute axis orthogonal to the inlet overflow weir axis and with the flow through the weir in the same direction as the chute axis



2.0.5



side channel spillway



free overflow spillway with the chute axis approximately parallel to the inlet overflow weir axis and with the flow through the weir approximately perpendicular to the chute axis direction



2.0.6



ski jump spillway



free overflow spillway with the inlet control section at dam top, which discharges the water into river channel by making the water away from the dam toe with chute through flip shot



2.0.7



free overflow tunnel spillway



spillway with all or part of the mountain body on the bank being tunnel, and with the discharged water having free surface within the whole course



2.0.8



control section



weir or sluice (hereinafter referred to as weir) located between the intake canal and the chute to control the discharge of the spillway as well as the buildings connected on both sides



2.0.9



chute



rapids discharge channel between the inlet control section and the outlet energy dissipation section of the spillway



2.0.10



flip bucket



bucket built at the end of the outlet structure, capable of ejecting the discharged water downstream and having a certain reverse arc radius and a certain angle



2.0.11



energy dissipation by hydraulic jump



energy dissipation mode dissipating the residual energy of the rapids discharged from the outlet structure by making use of hydraulic jump so that the rapids are changed into slow flow and join in the downstream water, also called as hydraulic jump energy dissipation



2.0.12



ski-jump energy dissipation



energy dissipation mode ejecting the discharged rapids by the flip bucket built at the end of the outlet structure so that the rapids forms aerated jet flow and falls into the downstream water cushion



2.0.13



energy dissipation by hydraulic jump with step-down floor



energy dissipation mode by hydraulic jump formed by setting step-down floor of certain height at the reverse arc section end and at the head of the stilling pool of the energy dissipation by hydraulic jump



2.0.14



continuous flip bucket



continuous solid flip bucket built at the end of a outlet structure



2.0.15



slotted flip bucket



flip bucket consisting of platforms and trenches in an alternate way or those with different cantilever angles set at different elevations



2.0.16



slit-type flip bucket



flip bucket with the side wall of the chute at the outlet of the rapids forming slit due to sharp contraction



2.0.17



special-shaped convergent flip bucket



special shape flip bucket formed by bottom surface twisting, angle-cutting at bucket end or other means



2.0.18



apron



rigid bottom protection structure built at the downstream of the outlet structure to protect the riverbed from scour



2.0.19



cavitation



water flow phenomenon of occurrence of cavity (involving the occurrence, development and perish of the cavity) when the absolute pressure of a certain place in high velocity flow is lower than the vaporization pressure of that place



2.0.20



cavitation damage (pitting)



denudation deterioration of solid boundaries due to cavitation



2.0.21



jet-flow atomization



physical phenomena of rain and fog caused by splashing and splitting of jet-flow energy dissipation nappe



3 Spillway layout



3.1 General requirements



3.1.1 Spillway may consist of buildings such as intake canal, control section, chute, energy dissipation and scour prevention facilities, and outlet canal.



3.1.2 Spillway layout shall be selected through technical and economic comparison based on factors such as topography, geology, hub layout, dam type, construction, ecology and environment, operation management and economic indicators.



3.1.3 For spillway layout, attention shall be paid to coordination of contradictions in the layout of buildings for flood discharge, power generation, shipping, floatage drainage, fish passage, ecology, water supply and irrigation, so as to avoid mutual interference and take into account the requirements of architectural landscape.



3.1.4 When suitable topographical and geological conditions are available, the spillway may be arranged as main spillway and emergency spillway according to the flood characteristics and its influence on the downstream through technical and economic comparison demonstration, and the spillway shall meet the following requirements:



1 Main spillway and emergency spillway should be arranged separately; centralized arrangement, if adopted, shall be fully demonstrated.



2 Emergency spillway should be of open type. Self-collapsing type or a blasting-induced collapse type, after being demonstrated, may also be adopted.



3 The downstream structure in the control section of emergency spillway may be simplified in combination with the topographical and geological conditions, but it shall not affect the safety of main buildings.



3.1.5 With main and emergency spillways arranged, the main spillway discharge capacity shall not be less than the discharge ought to be borne by the spillway under the design flood standard. The use standard of emergency spillway shall be determined according to the factors such as project grade, hub layout, dam type, flood characteristics and standards, reservoir capacity characteristics and influence on downstream. During flood discharge through emergency spillway, the maximum total discharge of the reservoir shall not exceed the natural peak discharge of the dam site with the same frequency.



3.1.6 Spillway discharge, total width of overflow front edge and elevation of weir crest or sluice bottom plate shall be selected through technical and economic comparison based on the following factors:



1 Reservoir characteristics and flood dispatching;



2 Coordination with other outlet structures in layout and application;



3 Topographical and geological conditions, and scour resistance of downstream riverbed and both banks;



4 River channel characteristics and energy dissipation requirements;



5 Connection with adjacent buildings;



6 Sluice type and sizing;



7 Operation and maintenance conditions;



8 Cost and maintenance charge.



3.1.7 Spillway shall be arranged on the bank or pass according to the topographical and geological conditions. It is appropriate to avoid high side slopes formed by excavation and to avoid gullies, collapse bodies and landslide bodies.



3.1.8 When the mountain on both sides of the dam site is steep and no pass is available, the side channel spillway, ski jump spillway or free overflow tunnel spillway may be adopted through technical and economic comparison. The layout shall meet the following requirements:



1 The layout of side channel spillway and that of dam abutment shall be coordinated;



2 The layout of the inlet section and control section of the ski jump spillway and that of the dam body and other buildings in the dam area;



3 The tunnel line layout of the tunnel section and cross section design of free overflow tunnel spillway shall meet the relevant provisions of SL 279.



3.1.9 Spillway shall be arranged on a stable foundation, taking into account the structural characteristics of the rock mass and geological structure, as well as the adverse effects of changes in hydrogeological conditions on the stability of buildings and side slopes after the construction of the reservoir.



3.1.10 When the spillway is close to the dam abutment, its layout and discharge shall not affect the stability of the dam abutment and bank slope. In the earth-rockfill dam hub, the joints, guide walls, chute side walls, etc. connected with the dam shall be safe and reliable.



3.1.11 Spillway layout shall make the water flow smooth and the axis should be straight. If it is necessary to turn for the axis, the bend should be set in the section of the intake or outlet canal.



3.1.12 For the spillway, layout of flood discharge energy dissipaters and the type of flood discharge energy dissipation shall be reasonably chosen. The outlet flow of it shall be smoothly connected with the downstream river channel to avoid serious scouring and siltation of the downstream riverbed and bank slopes of the dam site caused by the discharged water, which will affect the normal operation of other buildings in the hub.



3.1.13 The sluice hoisting equipment and basic pumping and drainage equipment of spillway shall be provided with standby power supply and powered reliably.



3.2 Intake canal



3.2.1 The layout of the intake canal shall follow the following principles:



1 Favorable topographical and geological conditions shall be selected.



2 The selection of the axis direction shall make the water inflow smooth, with good flow state;



3 When the channel is long and a transition section is set in front of the control section, the length of the transition section shall be determined according to conditions such as flow velocity, and shall not be less than 2 times the water depth in front of the weir;



4 When the canal turns, the turning radius of the axis should not be less than 4 times the width of the canal bottom, and there shall be a straight section with length not less than 2 times the water head on the weir between the bend and the weir.



3.2.2 The inlet layout of the intake canal shall be adjusted to local conditions to make the water flow smoothly into the canal. The inlet shape shall be simple and meet the following requirements:



1 When the inlet is arranged at the dam abutment, a curved guide wall in the water flow direction shall be arranged on the side close to the dam, and the side close to the mountain shall be excavated or lined into a regular curved surface;



2 When the inlet is arranged at the pass, it should be arranged in a symmetrical or basically symmetrical bell mouth type.



3.2.3 The bottom width of the intake canal may be of equal width or reduce along the direction of water flow. The ratio of the bottom widths of the head and end of the intake canal should be 1~3. The joint with the control section shall be of equal width with the overflow front edge. The bottom plate should be flat or reverse slope slightly inclining towards upstream.



3.2.4 The bottom of the intake canal may not be lined; when the head loss is large, the canal bottom lining shall be determined through economic comparison. When the requirements of non-flushing flow rate are not met, lining shall be applied.



3.2.5 The type of the leading wall in the control section of the intake canal shall make the flow state good. The length of the leading wall along the water flow direction should be greater than 2 times the water depth in front of the weir, and the wall top shall be higher than the highest reservoir water level during flood discharge.



3.2.6 The intake canal guide wall close to the earth-rockfill dam body shall meet the following requirements:



1 The lower limit of the length of the guide wall in water flow direction shall be such that the slope toe of the adjacent dam is blocked;



2 The top of the guide wall within the range 2 times the depth of water in front of the weir in the control section shall be higher than the highest reservoir water level during flood discharge.



3 The guide wall beyond the range 2 times the depth of water in front of the dam may be set as submerged type, with the top of the wall higher than the dam surface by an appropriate height.



4 The guide wall layout and structural design shall meet the requirements of seepage prevention and stability, and shall be coordinated with dam seepage prevention system and deformation.



3.3 Control section



3.3.1 The control section shall include weirs and buildings connected on both sides.



3.3.2 The weir layout shall meet the following requirements:



1 Overall consideration shall be given to the general layout requirements of intake canal, chute, energy dissipation and scour prevention facilities and outlet canal;



2 Requirements of buildings on bearing capacity, stability, seepage resistance and durability of foundation;



3 It shall facilitate external traffic and the layout of buildings on both sides;



4 When the weir is close to the dam abutment, it shall be coordinated with the dam layout.



5 It shall be convenient to arrange the anti-seepage system so that the weir and the systems for water stop, anti-seepage and drainage on both banks or of the dam form a whole.



3.3.3 The weir type shall be selected through comparison according to the topographical and geological conditions, hydraulic conditions, application requirements and technical and economic indicators, and open overflow weir should be selected. Weir types of practical weirs, broad crested weirs, hump weirs that are open or with breast wall orifice may be adopted.



3.3.4 The weir crest elevation, overflow front edge length, weir crest sluice setting, sluice type, sluice size and quantity, sluice pier type and size, etc. shall be determined through technical and economic comparison, taking into account factors such as engineering safety, flood dispatching, operating conditions, inundation loss, engineering investment, etc.



3.3.5 The setting of overhaul sluice shall be determined according to the engineering safety and operation needs. When the overflow weir crest is under water all the year round, an overhaul sluice shall be set.



3.3.6 The side weir of the side channel spillway may be practical weir. Narrow and deep trapezoidal cross-section should be adopted as the side channel cross-section. The slope ratio of the side slope close to the mountain may be determined according to the geological conditions. The side slope close to the weir should not be steeper than 1:0.5.



3.3.7 The type and size of sluice piers shall meet the requirements for layout of sluice, traffic bridge and working bridge, water flow conditions, structure, operation and maintenance, etc.



3.3.8 The layout of the working bridge and traffic bridge on the weir shall be determined according to the requirements of project operation, observation, overhaul, traffic and sluice hoisting equipment layout. The clearance under the bridge shall meet the requirements of flood discharge and floatage drainage. When flood control and emergency rescue are required, traffic bridge and working bridge shall be set up separately.



3.3.9 The elevation of the sluice pier and the top of bank wall at the control section shall meet the following requirements:



1 When discharging the check flood, it shall not be lower than the check flood level plus heightening value for safety.



2 When retaining water, it shall not be lower than the design flood level or the normal water storage level plus the calculated wave height and heightening value for safety.



3 When the spillway abuts against the dam abutment, the top elevation of the control section shall be coordinated with that of the dam crest.



4 The lower limit heightening value for safety shall be selected according to Table 3.3.9.

Foreword ii
1 General provisions
2 Terms
3 Spillway layout
3.1 General requirements
3.2 Intake canal
3.3 Control section
3.4 Chute
3.5 Energy dissipation and scour prevention facilities
3.6 Outlet canal
4 Hydraulic design
4.1 General requirements
4.2 Intake canal
4.3 Control section
4.4 Chute
4.5 Energy dissipation and scour prevention
4.6 Outlet canal
4.7 Anti-cavitation damage design
4.8 Jet-flow atomization and anti-icing design
5 Structural design
5.1 General requirement
5.2 Intake canal lining
5.3 Control section
5.4 Chute bottom slab
5.5 Flip bucket
5.6 Stilling pool base slab
5.7 Side walls
5.8 Downstream protection
6 Design of foundation and side slope treatment
6.1 General requirement
6.2 Foundation excavation
6.3 Consolidation grouting
6.4 Seepage prevention and drainage of the foundation
6.5 Fault, weak interlayer and karst treatment
6.6 Side slope excavation and treatment
7 Safety monitoring design
7.1 General requirement
7.2 Monitoring items
Annex A Calculation equations for hydraulic design
A.1 Weir surface curve
A.2 Equation for calculating discharge capacity
A.3 Hydraulic calculation of chute
A.4 Ski-jump energy dissipation
A.5 Slit-type ski-jump energy dissipation
A.6 Energy dissipation by hydraulic jump
A.7 Design to prevent cavitation damage of water flow
A.8 Table of roughness values commonly used in hydraulic calculation
Annex B Calculation of anti-floating stability of stilling pool bottom slab
B.1 Load combinations and calculation equations
B.2 Load calculation
Explanation of wording in this specification

1 总则
1.0.1 为规范溢洪道设计，做到安全可靠、经济合理、技术先进、环境协调、管理运行方便，制定本标准。
1.0.2 本标准适用于大、中型水利水电工程中岩基上的1级、2级、3级溢洪道(包括滑雪道式溢洪道、溢洪洞)的设计，4级、5级溢洪道设计可参照使用。
1.0.3 溢洪道洪水标准(包括溢洪道消能防冲建筑物洪水标准)应根据溢洪道的级别，按照SL252《水利水电工程等级划分及洪水标准》的规定确定。
1.0.4 大型工程或水力条件较复杂的中型工程的溢洪道，应根据水工模型试验，论证工程布置及水力设计的合理性。
1.0.5 溢洪道设计应根据工程防洪调度要求等，确定溢洪道运行和闸门启闭方式。
1.0.6 本标准主要引用下列标准：
GB/T 50662 水工建筑物抗冰冻设计规范
GB 51247 水工建筑物抗震设计规范
SL 74 水利水电工程钢闸门设计规范
SL 191 水工混凝土结构设计规范
SL 252 水利水电工程等级划分及洪水标准
SL 265 水闸设计规范
SL 279 水工隧洞设计规范
SL 319 混凝土重力坝设计规范
SL 379 水工挡土墙设计规范
SL 386 水利水电工程边坡设计规范
SL 486 水工建筑物强震动安全监测技术规范
SL 616 水利水电工程水力学原型观测规范
SL 654 水利水电工程合理使用年限及耐久性设计规范
SL 725 水利水电工程安全检测设计规范
SL 744 水工建筑物荷载设计规范
DL/T 5207 水工建筑物抗冲磨防空蚀混凝土技术规范
1.0.7 溢洪道设计除应符合本标准规定外，尚应符合国家现行有关标准的规定。
2 术语
2.0.1 正常溢洪道 main spillway
单独或联合其他泄水建筑物，泄流能力满足设计洪水标准要求、经常使用的溢洪道。
2.0.2 非常溢洪道 emergency spillway
宣泄超过设计洪水标准的非I正常洪水的溢洪道。
2.0.3 开敞式溢洪道 free overflow spillway
进口控制段为开敞，且下泄水流具有自由表面的溢洪道。
2.0.4 正槽式溢洪道 normal channel spillway
泄槽轴线与进口溢流堰轴线正交，过堰水流与泄槽轴线方向一致的开敞式溢洪道。
2.0.5 侧槽式溢洪道 side channel spillway
泄槽轴线与进口溢流堰轴线大致平行，过堰水流与泄槽轴线方向接近垂直的开敞式溢洪道。
2.0.6 滑雪道式溢洪道ski jump spillway
进口控制段位于坝顶，通过泄槽将水流挑射到远离坝脚处排入河道的开敞式溢洪道。
2.0.7 溢洪洞 free overflow tunnel spillway
在岸边山体内全部或部分为隧洞，下泄水流全程具有自由表面的溢洪道。
2.0.8 控制段 control section
位于进水渠与泄槽间控制溢洪道泄量的堰或闸(以下简称为堰)及两侧连接建筑物。
2.0.9 泄槽 chute
溢洪道进口控制段与出口消能段之间的急流泄水道。
2.0.10 挑坎 flip bucket
建在泄水建筑物末端，能将下泄水流向下游抛射，具有一定反弧半径和一定角度的坎，又称挑流鼻坎。
2.0.11 底流消能 energy dissipation by hydraulic jump
利用水跃消除从泄水建筑物泄出急流的余能，将急流转变为缓流与下游水流相衔接的消能方式，又称水跃消能。
2.0.12 挑流消能 ski—jump energy dissipation
在泄水建筑物末端设置挑坎，将泄出的急流挑向空中，形成掺气射流落入下游水垫的消能方式。
2.0.13 跌坎底流消能 energy dissipation by hydraulic jump with step - down floor
在底流消能反弧段末端、消力池池首设置一定高度的跌坎而形成的底流消能方式。
2.0.14 连续挑坎 continuous flip bucket
建在泄水建筑物末端的连续实体挑坎。
2.0.15 差动挑坎slotted flip bucket
由齿台和沟槽相间构成的或设于不同高程有不同挑角的挑坎。
2.0.16 窄缝挑坎slit - type flip bucket
急流出口处的泄槽边墙急剧收缩形成窄缝的挑坎。
2.0.17 异型挑坎 special - shaped convergent flip bucket
通过底面扭曲、坎端切角或其他方式所形成的特殊体形挑坎。
2.0.18 护坦 apron
建于泄水建筑物下游保护河床不受冲刷破坏的刚性护底建筑物。
2.0.19 空化 cavitation
在高速水流中某处的绝对压强低于该处的汽化压强时，出现含空穴(涉及空穴的发生、发展与溃灭)的水流现象。
2.0.20 空蚀 cavitation damage (pitting)
由于空化所引起的固体边界的剥蚀破坏。
2.0.21 泄洪雾化 jet - flow atomization
泄洪消能水舌激溅、裂散等形成雨雾的物理现象。
3 溢洪道布置
3.1 一般规定
3.1.1 溢洪道可由进水渠、控制段、泄槽、消能防冲设施及出水渠等建筑物组成。
3.1.2 溢洪道布置应根据地形、地质、枢纽布置、坝型、施工、生态与环境、运行管理及经济指标等因素，经技术经济比较选定。
3.1.3 溢洪道布置应注意协调泄洪、发电、航运、排漂、过鱼、生态、供水及灌溉等建筑物在布置上的矛盾，避免相互干扰，并兼顾建筑景观要求。
3.1.4 在具备合适的地形、地质条件时，根据洪水特性及对下游的影响等，经技术经济比较论证，溢洪道可布置为正常溢洪道和非常溢洪道，且应符合下列规定：
1 正常溢洪道和非常溢洪道宜分开布置；若采用集中布置，应充分论证；
2 非常溢洪道宜采用开敞式，经论证亦可采用自溃式或爆破引溃式；
3 非常溢洪道控制段下游结构可结合地形、地质条件简化，但不得影响主要建筑物安全。
3.1.5 设有正常、非常溢洪道时，正常溢洪道泄洪能力不应小于设计洪水标准下溢洪道应承担的泄量。非常溢洪道启用标准应根据工程等级、枢纽布置、坝型、洪水特性及标准、库容特性及对下游的影响等因素确定。非常溢洪道泄洪时，水库最大总下泄流量不应超过坝址同频率天然洪峰流量。
3.1.6 溢洪道泄量、溢流前缘总宽度及堰顶或闸底板高程等，应根据下列因素通过技术经济比较选定：
1 水库特性及洪水调度；
2 与其他泄水建筑物在布置和运用上的协调；
3 地形、地质条件，下游河床及两岸抗冲能力；
4 河道特性及消能要求；
5 与相邻建筑物的连接；
6 闸门型式及定型尺寸；
7 运用及检修条件；
8 造价及维护费用。
3.1.7 溢洪道应根据地形和地质条件布置在岸边或垭口，宜避免开挖形成高边坡，且宜避开冲沟、崩塌体及滑坡体。
3.1.8 坝址两岸山势陡峻，无可利用垭口时，经技术经济比较，可采用侧槽式溢洪道、滑雪道式溢洪道或溢洪洞。其布置应符合下列规定：
1 侧槽式溢洪道布置应与坝肩布置相协调；
2 滑雪道式溢洪道的进口段及控制段布置应与坝体及坝区其他建筑物布置相协调；
3 溢洪洞隧洞段洞线布置与断面设计应符合SL 279的有关规定。
3.1.9 溢洪道应布置在稳定的地基上，并应考虑岩体结构特征和地质构造，以及建库后水文地质条件的变化对建筑物及边坡稳定的不利影响。
3.1.10 溢洪道靠近坝肩时，其布置及泄流不得影响坝肩及岸坡的稳定。在土石坝枢纽中，与大坝连接的接头、导墙、泄槽边墙等应安全可靠。
3.1.11 溢洪道布置应使水流顺畅，轴线宜取直线。如需转弯，弯道宜设置在进水渠或出水渠段内。
3.1.12 溢洪道应合理选择泄洪消能工布置和泄洪消能型式，其出口水流应与下游河道平顺衔接，避免下泄水流对坝址下游河床和岸坡的严重淘刷、冲刷以及河道淤积，影响枢纽其他建筑物的正常运行。
3.1.13 溢洪道的闸门启闭设备及基础抽排水设备，应设置备用电源，且供电可靠。
3.2 进水渠
3.2.1 进水渠布置应遵循下列原则：
1 应选择有利地形、地质条件；
2 选择轴线方向时，应使进水顺畅、流态良好；
3 渠道较长且控制段前设置渐变段时，渐变段长度视流速等条件确定，不宜小于2倍堰前水深；
4 渠道转弯时，轴线转弯半径不宜小于4倍渠底宽度，弯道至堰宜有长度不小于2倍堰上水头的直线段。
3.2.2 进水渠进口布置应因地制宜，使水流平顺入渠，体型宜简单，且应符合下列要求：
1 进口布置在坝肩时，靠坝一侧应设置顺应水流的曲面导水墙，靠山一侧宜开挖或衬护成规则曲面；
2 进口布置在垭口时，宜布置成对称或基本对称的喇叭口型式。
3.2.3 进水渠底宽可为等宽或顺水流方向收缩，进水渠首、末端底宽之比宜为1~3，在与控制段连接处应与溢流前缘等宽。底板宜为平底或坡度不大倾向上游的反坡。
3.2.4 进水渠渠底可不衬护；水头损失较大时，渠底衬护应通过经济比较确定；不满足不冲流速要求时，应衬护。
3.2.5 进水渠控制段前导墙型式应使水流流态良好，导墙顺水流方向的长度，宜大于堰前水深的2倍，墙顶应高于泄洪时最高库水位。
3.2.6 紧靠土石坝坝体的进水集导墙应符合下列要求：
1 导墙顺水流向长度应以挡住邻接的大坝坡脚为下限；
2 控制段2倍堰前水深距离以内的导墙，其墙顶应高出泄洪时最高库水位；
3 2倍堰前水深长度以远的导墙，可设置为下潜式，但墙顶应高出坝面适当高度；
4 导墙布置与结构设计应满足防渗及稳定要求，并与坝体防渗系统及变形相协调。
3.3 控制段
3.3.1 控制段应包括堰及两侧连接建筑物。
3.3.2 堰的布置应满足下列要求：
1 统筹考虑进水渠、泄槽、消能防冲设施及出水渠的总体布置要求；
2 建筑物对地基承载能力、稳定性、抗渗性及耐久性要求；
3 便于对外交通和两侧建筑物布置；
4 堰靠近坝肩时，应与大坝布置相协调；
5 便于防渗系统布置，使堰与两岸或大坝的止水、防渗、排水系统形成整体。
3.3.3 堰的型式应根据地形地质条件、水力条件、运用要求及技术经济指标等比较选定，宜选用开敞式溢流堰。堰型可选用开敞或带胸墙孔口的实用堰、宽顶堰、驼峰堰等型式。
3.3.4 堰顶高程、溢流前缘长度、堰顶闸门设置、闸门型式、闸门尺寸及数量、闸墩型式及尺寸等，应考虑工程安全、洪水调度、运行条件、淹没损失、工程投资等因素，经技术经济比较确定。
3.3.5 检修闸门设置应根据工程安全、运行需要确定。溢流堰顶常年位于水下时，应设置检修闸门。
3.3.6 侧槽式溢洪道的侧堰可采用实用堰。侧槽断面宜采用窄深式梯形断面，靠山侧边坡坡比可根据地质条件确定，靠堰一侧边坡不宜陡于1:0.5。
3.3.7 闸墩型式和尺寸应满足闸门、交通桥和工作桥布置、水流条件、结构及运行检修等要求。
3.3.8 堰上工作桥、交通桥布置，应根据工程运行、观测、检修、交通以及闸门启闭设备布置等要求确定。桥下净空应满足泄洪及排漂要求。有防洪抢险要求时，交通桥与工作桥应分开设置。
3.3.9 控制段闸墩及岸墙顶部高程满足下列要求：
1 在宣泄校核洪水时不应低于校核洪水位加安全加高值。
2 挡水时不应低于设计洪水位或正常蓄水位加波浪计算高度和安全加高值。
3 溢洪道紧靠坝肩时，控制段顶部高程应与大坝坝顶高程协调。
4 安全加高下限值按表3.3.9选取。
表3.3.9 安全加高下限值 单位：m
运用工况 控制段建筑物级别
1级 2级 3级
挡水 0.7 0.5 0.4
泄洪 0.5 0.4 0.3
5 波浪要素计算应符合SL 744的相关规定。波浪计算高度应取累计频率为1%的波高加上波浪中心线与设计水位的高差。
3.4 泄槽
3.4.1泄槽轴线宜采用直线，当必须设置弯道时，弯道宜设置在流速较小、水流较平稳、底坡较缓且无变化的部位。
3.4.2 泄槽在平面上设置弯道时，应符合下列要求：
1 横断面内流速分布均匀；
2 冲击波对水流扰动影响小；
3 在直线段和弯段之间，可设置缓和过渡段；
4 为降低边墙高度和调整水流，宜在弯道及缓和过渡段渠底设置横向坡；
5 矩形断面弯道轴线的曲率半径宜采用6~10倍泄槽宽度；
6 单宽泄量大、流速高的泄槽弯道参数宜通过水工模型试验确定。
3.4.3 泄槽纵坡、平面布置及横断面形式，应根据地形、地质条件及水力条件等通过技术经济比较确定，且应符合下列要求：
1 泄槽纵坡宜大于水流的临界坡。当条件限制需要变坡时，纵坡变化不宜过多，且宜先缓后陡。
2 泄槽横断面宜采用矩形断面。当结合岩石开挖采用梯形断面时，边坡宜采用较陡边坡，并应注意由此引起的流速不均匀问题。
3 泄槽沿轴线宜为等宽，当需要变化泄槽宽度时，变化角度可按附录A.3.3确定。
3.4.4 具有两个及以上泄洪孔口的溢洪道，结合运行要求，必要时可在泄槽内设置中隔墙。
3.4.5 泄槽边墙顶高程，应根据水面波动及水流掺气等因素影响后的水面线，加0.5~1.5m安全加高；对于收缩(扩散)段、弯道段等水力条件比较复杂及流速较大的部位，宜取大值。
3.5 消能防冲设施
3.5.1 消能防冲设施可采用挑流消能、底流消能或其他消能型式。具体型式应根据地形、地质和泄流条件，结合建筑物运行方式、下游水深及河床抗冲能力、下游水流衔接、泄洪、雾化及对其他建筑物的影响等，通过技术经济比较选定。
3.5.2 消能设施应符合下列规定：
1 对于消能防冲设计标准的洪水及以下各级洪水，尤其是常遇洪水及可能出现的不利情况，应结构可靠、消能效率高，并具有良好的防空蚀、抗磨蚀、抗冰害能力；
2 对超过消能防冲设计标准的洪水，允许消能防冲建筑物出现局部破坏，但不应危及大坝及其他主要建筑物安全，且应易于修复，不影响枢纽长期运行；
3 淹没于水下的消能设施宜具备检修条件。
3.5.3 挑流消能适用于岩石地基的高、中水头枢纽。挑坎可采用等宽连续挑坎、差动挑坎、窄缝挑坎或异型挑坎等型式，应根据枢纽布置及下游河床的情况确定。对大泄量、窄河谷和地质条件较差的工程，宜采用窄缝挑坎或异型挑坎。
3.5.4 采用挑流消能遇下列情况时，应采取妥善措施处理：
1 地基存在延伸至下游的缓倾角层面及地质构造有可能被冲坑切断，危及建筑物的安全；
2 岸坡有可能被冲塌，危及坝肩稳定。堵塞出水渠或下游河道；
3 下游涌浪及回流危及大坝与其他建筑物的安全和正常运行。
3.5.5 采用挑流消能时，应研究雾化对枢纽及其他建筑物运行安全以及边坡稳定的影响，对于窄河谷、干旱少雨地区更应重视。坝下游的建筑物及露天电气设备、输电线路、交通道路宜避开强雾化区。多泥沙河流应重视泥雾的影响。
3.5.6 对流态有严格要求或有减免泄洪雾化影响的枢纽宜采用底流消能。底流消能应号虑泥沙磨蚀和空蚀的影响。
3.5.7 底流消能的消力池纵断面可采用平底式、斜坡式或多级消力池，横断面宜采用矩形，平面上宜采用等宽布置，必要时可采用扩散型布置。流速较小时，消力池内可布置辅助消能工。消力池具体型式应经技术经济比较确定。
3.5.8 消力池的尾坎可采用连续坎或差动坎等型式。消力池两侧边墙顶高程可根据池内水面线加适当安全加高确定，并应考虑岩体条件、水面波动与水流掺气及下游尾水等的影响。
3.5.9 池底流速较大的消力池宜采用跌坎底流消能或扩散跌坎底流消能。跌坎底流消能应根据水工模型试验确定跌坎高度、池底高程及池底宽度。
3.5.10 面流消能可用于下游尾水大于跃后水深且水位变幅不大，河床及两岸在一定范围内有较高的抗冲能力或有排漂要求的枢纽。必要时，下游可设置导墙。
3.5. 11 消力戽或戽式消能工可用于下游水深大于跃后水深、下游河床及两岸有一定抗冲能力的枢纽，有排漂要求时不宜采用。消力戽下游宜设置导墙。
3.5.12 台阶式消能的台阶布置在溢洪道泄槽内，适用于单宽流量较小的工程，台阶高度、宽度可参考类似工程经验选定。单宽流量较大或采用联合消能时，应通过模型试验论证。
3.6 出水渠
3.6.1 溢洪道下泄水流经消能后不能直接泄入河道且可能造成危害时，应设置出水渠。
3.6.2 出水渠轴线方向宜顺应下游河势，宽度应使水流不过分集中，并应防止折冲水流对河岸危害性淘刷。
3.6.3 出水渠防护措施应根据地形、地质条件和流速确定。
4 水力设计
4.1 一般规定
4.1.1 溢洪道水力设计宜包括下列内容：
1 泄流能力计算；
2 进水渠水力设计；
3 控制段水力设计；
4 泄槽水力设计；
5 消能防冲水力设计；
6 出水渠水力设计；
7 高速水流防空蚀设计；
8 泄洪雾化及防冰设计。
4.1.2 对于大型工程及水力条件较复杂的中型工程的溢洪道，其水力设计应经水工模型试验验证或专门研究。
4.1.3 溢洪道水力设计应满足下列要求：
1 泄流能力应满足设计和校核工况所要求的泄量；
2 体型合理、简单，水流平顺、稳定，并避免发生空蚀；
3 防空蚀设计应符合 DL/T 5207的有关规定。
4.1.4 溢洪道的水头损失包括沿程水头损失和局部水头损失。糙率系数可按附录A.8查用，局部阻力系数可根据有关资料分析选用。
4.2 进水渠
4.2.1 进水渠水力设计应使渠内水流平顺、稳定，水面波动及横向水面比降小，并应避免回流和漩涡。
4.2.2 进水渠的设计流速应大于悬移质不淤流速，小于渠道不冲流速，且水头损失小。不满足上述规定时，应进行论证。渠道设计流速宜采用3~5m/s。
4.2.3 渠道水面线可在引水渠渠首与堰前3~5倍堰上水头处的控制断面之间建立能量方程，采用分段求和法计算。
4.3 控制段
4.3.1 开敞式实用堰(包括正堰和侧堰)，堰顶下游面宜优先采用WES型幂曲线，堰顶上游堰头可采用双圆弧、三圆弧或椭圆曲线。堰面曲线可按附录A.1.1、附录A.1.2计算。
4.3.2 当选用低实用堰时，宜取上游堰高P1≥0. 3Hd、下游堰高P2≥0.6Hd (Hd为堰面曲线的定型设计水头)。堰面曲线下接直线段，坡度宜陡于1:1。
4.3.3 带胸墙孔口式溢流堰，当堰顶以上:最大水头Hmax与孔口高度D的比值Hmax/D>2，或闸门全开仍属于孔口泄流时，孔口下游堰面曲线宜采用抛物线，可按附录A.1.4计算。胸墙底缘可采用椭圆、圆弧或其他型式。
4.3.4 堰高较小的低堰，可采用驼峰堰或宽顶堰。驼峰堰堰面曲线参数可按附录A. 1.5选用。
4.3.5 堰的泄流能力可根据不同堰型选用附录A.2中的公式计算。
4.3.6 实用堰堰顶附近堰面压力应符合下列规定：
1 对于常遇洪水闸门全开情况，堰面不应出现负压；
2 对于闸门局部开启和校核洪水闸门全开情况，堰顶附近负压值不得大于0.06MPa。
3 闸门全开情况下堰顶附近的堰面负压值可按附表A.1.3查得。
4.3.7 闸墩墩头型式，应满足过堰水流平顺的要求，可采用圆弧或其他曲线形式。墩尾可采用曲线形或平头形。门槽型式可按SL 74的规定选用。
4.3.8 实用堰末端与泄槽连接段的反弧半径可取3~6倍反弧最低点最大水深。流速大时取大值。
4.3.9 侧槽溢洪道中侧槽段水力设计应满足下列要求：
1 侧槽底坡i，应取单一坡度，且小于按侧槽末端断面临界水深hke计算出的临界底坡ike。在宣泄设计流量时，槽内应为缓流。
2 侧槽首端断面水深超过堰顶的高度hs，应小于堰上水头Ho的一半，保证侧槽内为非淹没出流。
3 侧槽首、末端断面底宽比bu/be可采用0.5~1.0。
4 侧槽内和槽末断面处均不得产生水跃。槽末宜设置调整段，不宜紧接收缩段、弯道段。调整段长度L2可采用(2~3)hke，底坡宜水平。尾部升坎高度d可采用0.1~0.2倍泄槽首端断面临界水深hk。
5 侧槽段靠山一侧水面壅高Δh宜取平均水深h的10%~25%，必要时可经水工模型试验确定。
6 侧槽段水力计算可按附录A.3.5中的公式计算。