Study On Surrounding Rock Stability And Failure Modes Of Tunnel In Layered Rock Masses

Layered rock mass, due to the impact of the structural plane, the failure mechanism and failure mode is significantly different from other rock. Built in layered rock tunnel, the stability of surrounding rock and the failure mode issue is outstanding.In Chongqing the Nanchuan to Yajiang tunnel engineering of Fuling highway as the background, mainly by means of finite element numerical simulation, in view of the layered rock mass failure mode, deformation and failure mechanism of surrounding rock and the stability of surrounding rock are studied and analyzed, the main work includes:(1) Consider the special nature of the layered rock tunnel, based on the failure mechanism of the rock mass, layered rock runnel surrounding rock summed up the four typical failure modes, the bedding slip, bending fracture, squeeze the outer drum and wedge failure;(2) Strength reduction is applied to the tunnel stability analysis, numerical simulation and mechanical properties of the surrounding rock gradually weakening the stability of surrounding rock deformation and failure modes and mechanisms of instability and failure; contrast the size of the safety factor directly reflect the stability of the surrounding rock;(3) Through numerical analysis, to study different angle, different thickness, different jointset number of layered rock tunnel surrounding rock stability and failure mode.(4) Through numerical simulation, according to the deformation of surrounding rock, stress of surrounding rock and the plastic zone distribution and the size of the safety factor analysis of four aspects, in order to get the V level reasonable clear distance tunnel surrounding rock under the double hole.