The Stability Estimation of the Jointed Rock Mass Surrounding the Tunnel and Mechanism of the Shotcrete-bolt System-The Third Discussion of the Earth-pressure-

At present, one problem exisiting in the theory about the evaluation of the stability and the methods of calculation for surrounding rock of tunnel is that the structure design is disjointed to a certain extent from the geological works. The purposes in this paper are to obtain the formulas for discussing the stability, calculating the earth pressure, the safe joint-span ratio curve for discussing the stability of the surrounding rock and the formulas of the shotcrete-bolt lining design. These formulas are solved by the methods of rock mechanic theory and contain the elements such as the texture of surrounding rock, the natures of rock, the mechanical properties of the structure planes and the geometric dimensions of the tunnel. Therefore the problem as pointed out in upper the structure design is disjointed from the geological works shall be solved to a certain extent.