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(Design Guidelines for Energy Dissipation and Erosion Prevention of Water Discharge Structures)
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Basic data | Standard ID | NB/T 10392-2020 (NB/T10392-2020) | | Description (Translated English) | (Design Guidelines for Energy Dissipation and Erosion Prevention of Water Discharge Structures) | | Sector / Industry | Energy Industry Standard (Recommended) | | Classification of Chinese Standard | P59 | | Classification of International Standard | 27.140 | | Word Count Estimation | 139,143 | | Date of Issue | 2020-10-23 | | Date of Implementation | 2021-02-01 | | Regulation (derived from) | National Energy Administration Announcement No. 5 [2020] | | Issuing agency(ies) | National Energy Administration | NB/T 10392-2020: (Design Guidelines for Energy Dissipation and Erosion Prevention of Water Discharge Structures)
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(Design Guidelines for Energy Dissipation and Erosion Prevention of Water Discharge Structures)
ICS 27.140
P 59
NB
Energy Industry Standards of the People's Republic of China
Design Guidelines for Energy Dissipation and Erosion Prevention of Discharge Structures in Hydropower Projects
Guide for Design of Energy Dissipation and Erosion Control
for Water Release Structures of Hydropower Projects
2020-10-23 Release 2021-02-01 Implementation
Issued by the National Energy Administration
1 General
1.0.1 In order to unify the layout, body design, hydraulic design, and structural design of the energy dissipation and scour prevention of the water discharge structure of the hydropower project
This guideline is formulated to ensure safe operation, advanced technology, and reasonable economy.
1.0.2 This guideline is applicable to the design of energy dissipation and erosion prevention for water release structures of hydropower projects.
1.0.3 The design of energy dissipation and erosion prevention for the discharge structure of small hydropower projects can be simplified and implemented in accordance with this guideline.
1.0.4 The energy dissipation and anti-scouring design of discharge structures for hydropower projects in plain areas can be in accordance with the current industry standard "Sluice Design Code"
SL265 relevant regulations are implemented.
1.0.5 The design of energy dissipation and erosion prevention for water discharge structures of hydropower projects shall not only comply with this guideline, but also comply with the current relevant national regulations.
Standard provisions.
3 Basic regulations
3.0.1 The design of energy dissipation and erosion prevention for water discharge structures of hydropower projects shall include the protection of energy dissipation and erosion prevention structures, downstream river courses and bank slopes
Project layout, body design, hydraulic design, structural design, safety monitoring design.
3.0.2 The following data should be collected and analyzed in the design of energy dissipation and erosion control for water discharge structures of hydropower projects.
1 Weather, hydrology, sediment, topography, geology and other natural conditions.
2 Reservoir operation, social and ecological environment, flood control and shipping requirements.
3.0.3 The building level and flood standard of energy dissipation and erosion prevention buildings shall comply with the current industry standard "Hydropower Projects, etc.
Classification and design safety standard "DL 5180 related regulations.
3.0.4 The hydraulic design of energy dissipation and anti-scouring buildings shall meet the following requirements.
1 There should be a stable energy dissipating flow pattern and good energy dissipating effect during the operation of the design flood.
Has good hydrodynamic characteristics.
2 The outflow shall be coordinated with the requirements of adjacent hub buildings and downstream protection and navigation, and shall not affect other hubs
The normal operation of buildings and important downstream facilities.
3 The maintenance conditions during operation should be considered.
4 If the hydraulic conditions are complex or a new type of energy dissipater is used, preliminary calculations can be made based on the hydraulic numerical calculation and analysis results
Hydraulic design.
3.0.5 The structural design of energy dissipation and erosion-proof buildings shall meet the following requirements.
1 According to hydraulic characteristics and anti-floating and anti-sliding stability requirements, the structure, material properties, foundation anchoring, foundation
Basic processing and other design.
2 For concrete structures, the spacing of structural joints should be increased. The seam surface of the structural joint should be provided with a reliable closed water stop, and the bottom
It is advisable to set a keyway in the structural seam of the plate. Clear technical requirements should be put forward for the joint treatment of construction joints.
3 Temperature control and anti-cracking design should be carried out on the concrete structure.
4 According to engineering geology, hydrogeology conditions and operation and maintenance requirements, anti-seepage and drainage measures shall be adopted. Disappear after the dam
A closed drainage system should be installed in the force pool or water cushion pond.
5 The anchoring force standard value of the foundation anchor rod shall be in accordance with the current industry standard "Specification for Spillway Design" DL/T 5166 Medium Anchor
The effective weight of the solid foundation shall be calculated according to the relevant provisions of the current national standard "Rock and Soil Anchor and Shotcrete Support Engineering
The relevant provisions of "Technical Code" GB 50086 check the cross-sectional area of the bolt body and the length of the anchoring section.
6 Basic treatment measures should be proposed for the foundation rock mass.
3.0.6 The anti-erosion and anti-cavitation design of energy dissipation and anti-scouring buildings shall comprehensively consider the engineering's sediment characteristics and hydraulic characteristics, and the construction
The building structure, concrete raw materials and temperature control and anti-cracking requirements, construction technology and other factors shall meet the following requirements.
1 The size of the building should be reasonably determined, and aeration and corrosion reduction facilities should be installed.
2 The irregularity of the overflow surface should comply with the relevant regulations of the current industry standard "Specification for Spillway Design" DL/T 5166.
3 The strength grade of anti-erosion and anti-cavitation concrete should be determined according to the flow rate of water, and should not be lower than C30, but not suitable
Higher than C50.
4 The concrete of the energy dissipater slab should be poured continuously. When the erosion-resistant concrete is set on the surface of the bottom plate, it should be
The concrete is not layered and poured continuously.
5 The use of a new type of energy dissipater should carry out a decompression model test.
4 Energy dissipation type and layout
4.1 General rules
4.1.1 The overall layout of the energy dissipation and erosion control of the spillway building shall be based on the requirements of project development tasks, reservoir operation, environmental conditions, etc.
Requirements, comprehensive consideration of topographic and geological conditions, hub layout, connection of outlet water flow, downstream erosion resistance, bank slope stability,
Factors such as construction conditions, operation and maintenance, and project investment are determined through a comprehensive comparison of technology and economy.
4.1.2 Large and medium-sized hydropower projects with complex hydraulic conditions, and water discharge structures using joint energy dissipators or new types of energy dissipators.
The layout of energy dissipation and erosion prevention shall be subjected to hydraulic model test.
4.2 Energy dissipation type selection
4.2.1 According to the type of discharge structure and the location of the dissipator, the type of energy dissipation can be outlet energy dissipation or in-tunnel dissipation.
can.
4.2.2 The outlet energy dissipation can adopt energy dissipation methods such as underflow, jet flow, downflow, surface flow, and bucket flow. The specific selection should be in accordance with
The following requirements.
1 When there are navigation requirements in the downstream, poor geological bodies or atomization sensitive factors, undercurrent energy dissipation should be adopted.
2 When the high water head and medium water head and the flushing pit in the outlet energy dissipation area does not affect the safety of buildings and bank slopes, it is advisable to use a jet-driving
can.
3 When the downstream tail water is deep and the water level change is small, surface flow or turbulent flow can be used to dissipate energy.
4.2.3 The use of underflow energy dissipation in the energy dissipation method shall meet the following requirements.
1 When the height of the gravity dam is greater than 100 m, it is advisable to study the setting of auxiliary energy dissipation such as wide tail piers, step overflow surface, and falling sills.
work.
2 When the height of the dam exceeds 150 m or the flow velocity into the pond is greater than 40 m/s, the use of underflow energy dissipation should be demonstrated on a special topic.
4.2.4 The flip-flop energy dissipation method shall meet the following requirements.
1 According to the topography, geological conditions and adaptability of the downstream river valley, the layout type and body shape parameters of the ridge should be determined.
Do not scour the foundation of the building and the toe of the bank slope where the water falls.
2 When scouring pits affect the safety of buildings and bank slopes, the use of water cushion ponds, second dams, bank protection, bottom protection, etc. should be studied.
Process measures.
4.2.5 The energy dissipation in the cave can adopt swirl, orifice, hole plug and other energy dissipation types. The specific selection should meet the following requirements.
1 The downstream tunnel section of the swirling flow energy dissipation should be connected by open flow.
2 The energy dissipater in the orifice plate and the tunnel plug shall be arranged in the pressurized section of the tunnel.
4.2.6 When the discharge flow is large, the water head is high or the river valley is narrow, it is difficult to arrange a single energy dissipation type or the energy dissipation effect is ignored
When you want to, you can use the joint energy dissipation layout, and should meet the following requirements.
1 For the same discharge structure, additional auxiliary energy dissipators can be added to increase the energy dissipation rate, or two or more energy dissipators can be used
A combination of methods.
2 For different discharge structures, the outflows can collide, impact, and shear each other to increase the energy dissipation rate.
3 Decentralized layout and partitioned energy dissipation can be adopted.
4 When the overflow dam adopts underflow and turbulent flow to dissipate energy, wide tail piers can be arranged on the piers, and steps can be arranged on the overflow surface.
5 When the overflow surface hole of the arch dam adopts flip-flop and down-flow energy dissipation, it can be combined with the middle hole and bottom hole to form a left-right pair.
The combined energy dissipation type of rushing and up-and-down collision, but the impact of flood discharge atomization on other buildings should be fully considered. When downstream
When the atomization control factor is used, the side shrinkage and non-collision type can be adopted.
4.3 Downstream protection
4.3.1 The protection scope and type of the riverbed and bank slope downstream of the outlet of the energy dissipator shall be based on topographic and geological conditions, energy dissipation methods,
Analysis and determination of river hydraulic conditions or protection requirements of downstream affected objects.
4.3.2 When using the flip-flop energy dissipation, the impact of flood discharge atomization on the surrounding environment, bank slope stability, traffic conditions, and other factors should be analyzed and evaluated.
Adverse effects of the operation of the building, and take protective measures.
5 Design of underflow energy dissipation and erosion prevention
5.1 General provisions
5.1.1 The design of underflow energy dissipation and erosion prevention should include the following.
1 The body design of the stilling pool and auxiliary energy dissipater.
2 Perform hydraulic design on the water jump shape, water surface, flow velocity, and hydrodynamic pressure of the stilling pool.
3 The structural design of the energy dissipater, including concrete material performance and temperature control, structural joints and water stop, floor resistance
Floating stability, overall stability of side walls, foundation anchoring, structural reinforcement, foundation treatment, seepage prevention and drainage, etc.
5.1.2 The types of auxiliary energy dissipators, such as broad-tail piers, step overflow surfaces, falling sills, small sills, etc., shall be
Comprehensive analysis and determination of factors such as wide flow rate, downstream water depth, erosion resistance and cavitation erosion resistance.
5.2 Body shape design
5.2.1 The design of the stilling pool should meet the following requirements.
1 The plane of the stilling pool should be symmetrical, straight and of equal width. When the single-width flow into the pool is large, the bedrock erosion resistance is poor or
When the downstream water depth is shallow, the gradual expansion design can also be adopted.
2 The longitudinal section of the rectangular stilling pool can be determined according to the calculation results of the underflow energy dissipation hydraulic power. The calculation of the underflow energy dissipation hydraulic power is appropriate
Comply with the relevant regulations in Appendix A of this guideline. When the downstream water depth is insufficient, measures such as digging and setting tail sills can be used to increase
The depth of the pool.
3 The cross section of the stilling pool should be combined with bank slope excavation and side wall structure requirements, and rectangular or trapezoidal cross-section should be adopted.
5.2.2 The design of the flank pier shape should meet the following requirements.
1 The body shape parameters of the broad tail pier can be drafted in accordance with the relevant regulations and engineering experience in Appendix B of this guideline.
The model test is determined.
2 The shape of the wide tail pier should be coordinated with the layout of the gate chamber section of the overflow dam, and should not affect the discharge capacity and hinder the arc gate
Arrangement of hinge support.
3 The shape of the side hole wide tail pier should be asymmetrical, and the shrinking water tongue should not rush out of the downstream side wall.
5.2.3 When the step overflow surface is used in conjunction with flared piers, the following requirements shall be met.
1 The outflowing water tongue at the bottom of the wide tail pier should form an aerated cavity, and a small pick can be set before the first step on the overflow surface of the step.
The height of the front steps should be 1.5 m～2.0 m.
2 The lower part of the step overflow surface should be connected to the bottom plate of the stilling pool with a circular arc or a small angle.
5.2.4 When the flow velocity into the pool is greater than 30 m/s, it is advisable to set a sill at the entrance of the stilling pool to reduce the velocity at the bottom.
Jiyi meets the following requirements.
1 The entrance angle of the top of the sill and the height of the sill can be preliminarily drafted according to the upstream and downstream hydraulic conditions and similar engineering experience.
Determined by hydraulic model test.
2 The angle of entry into the pool should be horizontal or small depression angle, and the upstream and dam slope and drain channel should be transitionally connected by inverted arc section.
A certain length of straight line section should be set from the end to the top of the ridge.
3 The height of the sill shall be combined with the angle of entry into the pool and the height of the tail sill, according to the sill top into the pool flow rate, single-width flow, downstream water depth
Factors such as flow regime, bottom velocity, fluctuating pressure and other hydraulic indicators are considered comprehensively to determine the control requirements.
4 The side walls on both sides of the falling sill should be suddenly expanded at the same time, but cavitation damage to the downstream side wall should not be caused.
5.3 Hydraulic design
5.3.1 The hydraulic design of the stilling basin shall meet the following requirements.
1 The determined body shape of the stilling pool should ensure that a stable submerged water jump form can be formed at all levels of design discharge. Water jump
The submergence degree should be 1.05～1.10.
2 The height of the top of the side wall on both sides of the stilling pool should be determined according to the water depth in the pool during the design flood and the appropriate superelevation should be considered.
set.
3 It is not advisable to install auxiliary energy dissipators such as stilling piers in the area of the bottom of the stilling pool where the velocity is greater than 15m/s.
Cavitation damage occurred.
4 When the upstream of the stilling basin is connected with a steep slope discharge channel, the downstream total can be estimated according to the method of conjugate water depth ratio in Article A.0.5 of this guideline.
The water depth of the yoke is used to determine the shape of the hydraulic jump.
5 The downstream of the stilling pond tail sill should not produce a second hydraulic jump. The flow velocity, water surface fluctuation, and erosion and siltation form of the outgoing pool should meet the requirements of the development
Requirements for electricity, shipping and bank slope stability.
5.3.2 The hydraulic design of the underflow stilling pool of the wide tail pier shall meet the following requirements.
1 The length of the stilling pool can be preliminarily drafted as 2/3 of the length of the conventional flat-bottomed binary water jump stilling pool.
2 At all levels of design flow, a stable ternary water jump flow state should be formed in the stilling pool.
3 The impact area of the water tongue should have sufficient moving water cushion depth.
4 The shrinking water tongue after the pier should not smash the overflow dam surface or the side wall of the still pool.
5 If a stepped overflow surface is adopted, sufficient aeration should be ensured.
6 The flow pattern, energy dissipation effect, aeration and corrosion reduction performance, and hydrodynamic pressure characteristics of the overflow dam surface and the stilling pool should be
Model test verification.
5.3.3 The hydraulic design of the underflow stilling basin of the sill descent shall meet the following requirements.
1 The bottom elevation and longitudinal section body shape can be calculated according to the hydraulic calculation formula or hydraulic numerical calculation of the conventional flat bottom stilling pool
Analysis and development.
2 At all levels of design flow, a stable submerged water jump flow state should be formed in the stilling pool.
3 The main flow into the pool should have sufficient jet length to ensure sufficient diffusion and shear.
4 The flow pattern, flow velocity, hydrodynamic pressure and energy dissipation effect of the sill stilling pool should be verified by hydraulic model tests. Dip
The cavitation and cavitation erosion characteristics of the bottom plate and side wall of the sill and its downstream stilling pool should be subjected to a decompression model test.
5.4 Structural design
5.4.1 The anti-erosion and anti-cavitation design of the stilling pool shall meet the requirements of Article 3.0.6 of this guideline.
5.4.2 In the structural design, the concrete of the stilling pool should be adjusted according to the climate characteristics, construction conditions, structural characteristics and material properties.
Temperature control is required.
5.4.3 The structural stability check of the stilling pool shall meet the following requirements.
1 The bottom of the stilling pool should be checked for stability. The stability check calculation of the energy dissipater floor shall comply with the relevant provisions in Appendix C of this guideline.
Regulations.
2 The stability, base stress and section stress of the side walls on both sides of the stilling pool shall be checked.
3 The flow-induced vibration model test should be carried out for the stilling pool with complex hydraulic characteristics or with a new body shape.
5.4.4 The joints of the concrete structure of the bottom plate and side wall of the stilling pool in the hydraulic jump zone should meet the following requirements.
1 The spacing of structural slits parallel to the water flow direction can be 15 m～20 m.
2 The number of structural joints in the vertical direction of water flow should be reduced, and construction joints can be set according to the needs of construction and temperature control.
3 Adjacent structural seams can be staggered with each other.
4 Keyways should be provided for structural seams, and elastic materials should not be provided on the seam surface.
5.4.5 The water sealing of the structural joints of the stilling pool shall meet the following requirements.
1 There should not be less than 2 copper seals for structural joints.
2 A copper water stop should be set in the construction joint.
3 The construction technical requirements should be put forward for the performance of the water-stop material, the connection quality, and the concrete vibration of the water-stop part.
5.4.6 The design of the foundation anchor rod of the bottom plate of the stilling pool shall meet the requirements of Article 3.0.5 of this guideline. The exposed end of the foundation bolt
It should be anchored in the structural concrete, and should be connected with the steel mesh on the surface of the bottom plate.
5.4.7 The bottom of the stilling pool and the side wall foundation should be weakly weathered bedrock. The structural design should be based on the integrity of the bedrock and the structural surface
For the development situation, adopt basic treatment measures such as consolidation grouting...
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