This specification is formulated to standardize the design of hydraulic tunnels and ensure the design quality with the view of making use of the state-of-the-art technology， meeting the requirements for safety， applicability， cost-effectiveness， and rationality.
This specification is applicable to the design of Class 1， Class 2 and Class 3 hydraulic tunnels in water resources and hydropower projects， but not applicable to the design of hydraulic tunnels with steel linings in rock/soil mass.
Introduction to English Version
Foreword
1 General Provisions
2 Terms and Symbols
2.1 Terms
2.2 Symbols
3 Basic Data
4 Layout of Tunnels
4.1 Selection of Tunnel Alignment
4.2 Layout of Tunnel Inlets and Outlets
4.3 Layout of Multipurpose Tunnels
5 Pressure Status, Shape and Size of Tunnels
5.1 Selection of Pressure Status
5.2 Cross-Sectional Shape
5.3 Cross-Sectional Size
6 Hydraulic Design of Tunnels
6. 1 Principle of Calculation
6.2 Cavitation Damage Prevention Design of High-Velocity Tunnels
7 Design of Soil Tunnels
7.1 Supports and Linings of Soil Tunnels
7.2 Joints, Seepage Control and Waterstops for the Linings of Soil Tunnels
8 Design of Tunnels in Poor Ground
9 Tunnel Supports and Linings
9.1 General
9.2 Loads and Load Combinations
9.3 Unreinforced- and Reinforced-Concrete Linings
9.4 Prestressed Concrete Linings
9.5 Unlined and Bolt-Shotcrete Lined Tunnels
9.6 Design of Reinforced Concrete Lined Bifurcation
9.7 Joints in Linings
9.8 Design of Water-Retaining Plugs
10 Grouting, Seepage Control and Drainage of Tunnels
10.1 Grouting
10.2 Seepage Control and Drainage
11 Tunnel Operation and Maintenance
Annex A Head Loss Calculation for Hydraulic Tunnels
A. 1 Friction Losses
A. 2 Form Losses
Annex B Cavitation Damage Prevention Design of High-Velocity Tunnels
Annex C Calculation Method and Reduction Coefficient of External Water Pressure
Annex D Calculation of Concrete Lining Crack Width
Explanation of Wording
摘要
7.1.1 The design of soil tunnels shall meet the following requirements：
1 For longer tunnels， technical and economic comparison between conventional and shield construction method should be carried out.
2 For soil tunnels， the cross - section should be circular-shaped or horseshoe-shaped.
3 For soil tunnels， composite linings consisting of shotcrete or bolt-shotcrete and reinforced concrete should be adopted. High performance wet shotcrete should be used. The lining should be of integral structure. And structural measures shall be taken to prevent exfiltration.
4 Surface water and construction water in tunnels shall be properly diverted and drained.
5 For a soil tunnel connected with a rock tunnel， its support and lining shall extend into the rock tunnel for a sufficient length. The minimum overburden of rock tunnel at the transition shall not be less than the tunnel diameter.
7.1. 2 The surrounding rock pressure （load） on the lining structure of the soil tunnel shall be determined as follows：
1 For a soil tunnel which can form a ground arch， surrounding rock pressure may be estimated according to equilibrium theory of loose medium.
2 For a shallow soil tunnel which cannot form a ground arch， surrounding rock pressure should be calculated according to the gravity of overlying soil above the arch and adjusted based on topographical conditions and stabilization measures adopted in construction.
3 For a deep soil tunnel which cannot form a ground arch， surrounding rock pressure should be studied specially.
4 Swelling pressure shall be considered for swelling soil， and its value may be studied and determined through sampling tests or field tests.
5 For a tunnel portion with underground water， the loads acting on lining structure shall be determined by the joint action of soil and water pressure. For a tunnel portion with high external water pressure， if the soil mass cannot maintain its stability after being supported， measures including drainage and strengthening support or reinforcing the soil mass should be taken to reduce the load acting on lining structure.
6 Increased earth pressure induced by increased water content of soil caused by exfiltration in the operating period or other reasons shall be considered.
7.1. 3 The calculation of soil tunnel lining shall meet the following requirements：
1 For the calculation of shotcrete or composite lining consisting of bolt-shotcrete and reinforced concrete， the reinforced concrete lining may be designed as per a bearing structure， and calculated by structural mechanics methods. The bolt-shotcrete support may be estimated by the method given in GB 50086 or finite element method， and amended using experience derived from similar projects and construction monitoring results.
