Failure mode of soil-rock dual foundation pit based on rock mass stability
In order to explore the failure mode and judgment criteria of soil-rock dual foundation pit,this paper relied on specific cases,adopted PLAXIS 3D finite element numerical simulation software and strength reduction method to obtain the evolution rules of four types of foundation pit failure modes for different overlying soil thickness and the criteria for determining foundation pit failure modes for different underlying rock mass when the rock mass was stable.A unified analytical solution for the overall stability of arc,arc-plane,tangent plane and slip shear failure modes was derived by using the strip division method.According to the failure modes of sectional-plane and slip-shear,calculated the critical overlying soil thickness of different underlying rock mass,and derived the calculation formula of minimum supporting force to keep the rock mass incisal angle stable.The results showed that the failure mode of soil-rock dual foundation pit was different from that of soil foundation pit,and the strength and stability of rock mass should be fully considered.When the underlying rock mass was stable,with the increase of the thickness of the overlying soil layer,the failure mode of the soil-rock dual foundation pit gradually changed from circular failure to circular plane failure,tangent failure and sliding shear failure.The criterion of failure mode and the analytical solution of stability were reasonable.The research results could provide support and reference for the rational support of soil-rock dual foundation pit.
soil rock dual foundation pitvertical excavationfailure modestability analysisanalytical solution
NETL
NSTL
万方数据
