Experimental Study Of Weak Rock Tunnel Mechanical Traits, Different Stress Field

In accordance with the basilica study on the tunnel in different initial stress soft-weak surrounding rocks, 15 tunnel models with 3 later-compression coefficient (viz 0.5,1.0&1.5),are set up to study the mechanical characteristics of tunnels in the dissertation.According to different later-compression coefficient and prop time of timbering, 9 tunnel models are set up to study the effect of the earth pressure distribution of surrounding rocks due to excavation. The relationships between the loosen zone of tunnel radial earth pressure and the tunnel excavated diameter, the different later-compression coefficient and the exposed time are revealed. Based on the relationships between the earth pressure and the prop time, the suggestion that it's reasonable support time when the displacement is 200 mm of elevation direction in soft-weak surrounding rocks (The elastic modulus of surrounding rocks is 210 MPa), is put forward. And then the features of the tunnel deformation failure in rocks and linings are discussed by the breakdown test on 3 lining model and 3 grotto model..The process of constructing tunnels is simulated by setting up the FEM model. The characteristics of the stress and displacement in runnel surrounding rocks and tunnel linings are studied.