SL 279-2016 in English

Specification for Design of Hydraulic Tunnel1 General

1.0.1 This standard is formulated to standardize design of hydraulic tunnel, in order to make it safe in application, reasonable in economy, and advanced in technology.

1.0.2 This standard applies to design of Grades 1, 2 and 3 hydraulic tunnel in water resources and hydropower project while not applicable to that of hydraulic tunnel in lining of steel plate in rock and soil mass.

1.0.3 Grading of hydraulic tunnel shall be carried out according to the relevant requirements of GB 50201 Standard for Flood Control and SL 252 Standard for Classification and Flood Control of Water Resources and Hydroelectric Project. Corresponding grades may be raised or reduced via demonstration for the following conditions:

1 Grades 2 and 3 tunnel in particularly complicated geological conditions, with particularly high head and velocity and possibly causing serious losses after accident may raise one grade.

2 Tunnels with low head, low velocity and not causing serious losses after accident may reduce one grade.

1.0.4 Safety monitoring design of hydraulic tunnel shall meet relevant requirements of SL 725 Design Specification for Safety Monitoring in Water and Hydropower Projects.

1.0.5 Design of hydraulic tunnel shall meet overall project planning and environmental protection requirements.

1.0.6 The following standards are mainly referred in this standard:

GB/T 21120 Synthetic Fibres for Cement Mortar and Concrete
GB 50086 Specifications for Bolt-shotcrete Support
GB/T 50145 Standard for Engineering Classification of Soil
GB 50201 Standard for Flood Control
GB 50487 Code for Engineering Geological Investigation of Water Resources and Hydropower
SL 62 Construction Specification of Cement Grouting Used for Hydraulic Structures
SL 74 Hydraulic and Hydroelectric Engineering Specification for Design of Steel Gate
SL 191 Design Code for Hydraulic Concrete Structures
SL 203 Specifications for Seismic Design of Hydraulic Structures
SL 252 Standard for Classification and Flood Control of Water Resources and Hydroelectric Project
SL 253 Design Code for Spillway
SL 285 Design Specification for Intake of Hydraulic and Hydroelectric Engineering
SL 377 Technical Specification of Shotcrete and Rock Bolt for Water Resources and Hydropower Project
SL 725 Design Specification for safety Monitoring in Water and Hydropower Projects
DL/T 5207 Technical Specification for Abrasion and Cavitation Resistance of Concrete in Hydraulic Structures

1.0.7 Design of hydraulic tunnel shall comply with not only the requirements stipulated in this standard, but also those specified in the current relevant national standards.

2 Terms and Symbols

2.1 Terms

2.1.1 hydraulic tunnel

the flow channel with closed section that is excavated in mountain or underground

2.1.2 pressure tunnel

the hydraulic tunnel that is filled with water flow and bears the water pressure around the tunnel wall

2.1.3 free-flow tunnel

the hydraulic tunnel that is partially filled with water and whose water flow is provided with free surface

2.1.4 tunnel lining

the lining structure to guarantee stability of surrounding rock and good water flow conditions in the tunnel

2.1.5 tunnel support

the engineering measure to reinforce the surrounding rock in tunnel with structure or member and other materials

2.1.6 unlined tunnel

the hydraulic tunnel of which the most inner wall is unlined

2.1.7 system bolt

the bolt that is regularly arranged throughout excavation surface based on certain inter-row spacing according to stability requirements of rock body

2.1.8 filling grouting

the grouting work to fill cavity, hole or underground vacuum left by concrete structure by slurry so as to strengthen compactness of structure or foundation

2.1.9 consolidation grouting

the engineering measures to strengthen surrounding rock with geological defects (crack or fracture zone) by slurry so as to enhance its integrity and bearing capacity

2.1.10 chemical grouting

the engineering measure to grout the slurry with chemical material as main agent

2.1.11 tunnel transition section

the connection section that the tunnel gradually transits from a shape or size of section to another shape or size of section

2.1.12 convergent deformation

the actually measured displacement between two measuring points around underground chambers

Foreword i
1 General
2 Terms and Symbols
2.1 Terms
2.2 Symbols
3 Basic Information
4 Tunnel Arrangement
4.1 Selection of Tunnel Line
4.2 Entrance and Exit Arrangement
4.3 Layout of Multipurpose Tunnel
5 Pressure State and Type & Dimension of Tunnel
5.1 Selection of Pressure State
5.2 Sectional Shape
5.3 Sectional Dimension
6 Hydraulic Design of Tunnel
6.1 Calculation Principle
6.2 Anti-cavitation Design of Hydraulic Tunnel with High Velocity
7 Design of Soil Tunnel
7.1 Support and Lining of Soil Tunnel
7.2 Joint Division of Soil Tunnel Lining and its Anti-Seepage and Waterstop
8 Design of Tunnel Section at Adverse Geology
9 Tunnel Support and Lining
9.1 General Requirements
9.2 Loads and Load Combinations
9.3 Concrete and Reinforced Concrete lining
9.4 Prestressed Concrete Lining
9.5 Unlined and Anchor-shotcrete Lined Tunnel
9.6 Design of Reinforced Concrete Lining Bifurcated Tunnel
9.7 Joints on Lining
9.8 Design of Water Retaining Jam
10 Tunnel Grouting, Anti-seepage and Drainage
10.1 Grouting
10.2 Anti-seepage and Drainage
11 Tunnel Operation and Maintenance
Annex A Head Loss Calculation for Hydraulic Tunnel
Annex B High-velocity Anti-cavitation Design
Annex C External Water Pressure Calculation Method and Reduction Coefficient
Annex D Crack Width Calculation for Concrete Lining
Explanation of Wording
Authors for Previous Editions of this Standard