1 General Principles
1.0.1 So as to make the design and construction of bolt- shotcrete support project conform to requirements of advanced technology, economic feasibility, safety and application and guarantee quality, the standard is worked out.
1.0.2 The national standard is suitable for the design and construction of underground mine, access tunnel, hydraulic tunnel and all classes of cavern bolt-shotcrete support. It is also suitable for the all classes of rock side slopes bolt-shotcrete support construction.
1.0.3 For the design and construction of bolt-shotcrete support, the geologic investigation working for project must be done well and adjusted measures to local conditions, exactly and effectively reinforce wall rock, made full use of the self-supporting property of the wall rock.
1.0.4 The design and construction of bolt-shotcrete support not only observes the standard, but also conforms to relevant regulations of the current national standards.
2 Terms and Symbols
2.1 Terms
2.1.1 Initial support
When the design required the permanent support of the tunnel to be finished in stages, the timely construction support after tunnel excavation is called initial support.
2.1.2 Final support
After tunnel initial support is completed, when the wall rock is basically stabilized, it is that the tunnel periphery relative displacement and displacement velocity reach prescribed requirement, the final construction support is called final support.
2.1.3 Haunch
The haunch is the part from tunnel arch top to midpoint of arch springing arc length.
2.1.4 Convergence of tunnel inner perimeter
The distance variation of the tunnel periphery corresponding two points called convergence of tunnel inner perimeter.
2.1.5 Anchoring force
The generant restraining force of bolt to wall rock is called anchoring force.
2.1.6 Anti-pullforce
The force preventing bolt from pulling out from the rock mass is called anti-pull force.
2.1.7 Wetted perimeter
The perimeter of the wetted cross-section hydraulic tunnel is called wetted perimeter.
2.1.8 Point-loading strength index
It indicates the point-loading strength when the cylindrical standard test pieces with 50mm diameter are pressurized in radial direction.
2.1.9 System bolt
So as to make wall rock stabilize, the bolt groups on the tunnel periphery according to certain format collocation is called system bolt.
2.1.10 Prestress bolt
The prestress bolt is composed of anchor head, prestress bar and anchorage body, it indicates the long bolt which makes use of the elastic elongation of the prestress bar freedom section (stretching section) applying prestress to bolt so as to supply required initiative support tensile force. The specified prestress bolt in the national standard is the bolt whose amount of prestress is more than 200kN and its length is more than 8.0m.
2.1.11 Split set
The longitudinal split thin-wall steel tube is forced to thrust in the drill less than its outer diameter and take the friction and anchoring effect in virtue of radial thrust of steel tube to pore wall.
2.1.12 Swellex bolt
The abnormal cavity bolt manufactured by thin-wall steel tube is sent into the blast hole, take the anchoring effect by the generant friction which is produced by the high pressure water injection into the member and made it bulge.
2.1.13 Self-drilling bolt
It is integrated with blast hole, slurry injection and anchorage. The hollow drill string is the bolt as body of rod.
2.1.14 Shotcrete
The concrete mixture mixed with a certain ratio is sent to the injector head along pipe using compressed air or miscellaneous dynamics, they are injected vertically onto the sprayed surface with higher velocity, depending on the cement and aggregate continuous impaction and consolidation, the shotcrete is formed.
2.1.15 Sand enveloped by cement (SEC) shotcrete
The cement enveloped sand grout mixed with certain ratio and mixtures giving priority to coarse aggregate are sent to the sprayer mouth by using sand pump and injection machine respectively, after mixture, they are sprayed to the sprayed surface with high speed, and the formed concrete is called Sand enveloped by cement (SEC) shotcrete.
2.1.16 Reinforcing-bar truss Reinforcing-bar truss
It indicates the truss-type bracket which is formed by welding of steel bars.
1 General Principles
2 Terms and Symbols
2.1 Terms
2.2 Symbols
3 Wall Rock Classification
4. Bolt-shotcrete Support Design
4.1 General regulation
4.2 Bolt support design
4.3 Shotcrete support design
4.4 The bolt- shotcrete support design under special conditions
(I) Shallow-buried tunnel bolt-shotcrete support design
( II) The bolt-shotcrete support design for tunnel in plastic flow rock mass
(III) Paleoloess tunnel bolt-shotcrete support design
( IV) Hydraulic tunnel bolt-shotcrete support design
( V) The bolt-shotcrete support design for laneway influenced by exploitation
4.5 The bolt- shotcrete support design for side slope
5 On-site Supervision Measurement
5.1 General regulations
5.2 The content and method for on-site supervision measurement
5.3 The data processing and feedback for on-site supervision and measurement
6. Smooth blasting
7 Bolt Construction
7.1 General regulations
7.2 Fully grouted bolt construction
7.3 Tip anchorage type bolt construction
7.4 Friction-type bolt construction
7.5 Prestress bolt construction
7.6 The test and monitoring for prestress bar bolt
7.7 Self-drilling bolt construction
8 Shotcrete Construction
8.1 Raw material
8.2 Construction machinery
8.3 The mixtures mixing proportion and mixing
8.4 The preparation before injection
8.5 Injection operation
8.6 Steel fibre shotcrete construction
8.7 The reinforcing fabric shotcrete construction
8.8 Steel frame shotcrete construction
8.9 Cement enveloped sand shotcrete construction
8.10 The quality control for shotcrete strength
9 Safety Technique and Dustproof
9.1 Safety technique
9.2 Dustproof
10. Quality Inspection and Project Acceptance
10.1 Quality inspection
10.2 Project acceptance
Appendix A The shotcrete and wall rock cohesional strength test
Appendix B On-site supervision and measurement Table
Appendix C The prestress bolt fundamental test circulation load and unload class as well as displacement observation interval Table
Appendix D The drawing of shotcrete strength quality control figure
Appendix E The technical requirement for measuring shotcrete ash
Appendix F The shotcrete compressive strength standard test block execution method
Appendix G The bolt- shotcrete support construction record
