Simulation Study On Deformation And Failure Of Surrounding Rock Of Tunnel Crossing Soft And Hard Interbedding

China’s tunnel development has experienced a long process.In the process of tunnel construction,we often encounter adverse geological conditions passing through complex rock strata.Soft and hard interbedded rock mass is a particularly common adverse geological condition.Due to the special nature of soft and hard interbedded rock mass,it is impossible to fully grasp its mechanical properties.When excavating the tunnel under this geological condition,the surrounding rock of the tunnel is very prone to instability and collapse,resulting in engineering accidents.Therefore,the research on the mechanical properties of soft and hard interbedded rock mass has become a hot topic.Based on a tunnel project,this paper studies the influence of layer thickness ratio and layer thickness of soft and hard interbedded rock mass on the stability of tunnel surrounding rock.The effects of thickness ratio and thickness on mechanical properties and failure modes of soft-hard interbedded specimens were analyzed.After understanding its mechanical properties,cube model tests with different thickness ratios and thickness were prepared to further study the influence of thickness ratios and thickness on ultimate bearing capacity and macroscopic failure modes of tunnels.Finally,ABAQUS software was used to simulate tunnel excavation and analyze the influence of layer thickness ratio and rock layer thickness on the stability of tunnel surrounding rock.The main conclusions are as follows:(1)The results of the uniaxial compression experiment of the self-made soft and hard interlayer rock mass show that the rock mass strength and elastic modulus are positively correlated with the layer thickness ratio,the rock mass strength is positively correlated with the thickness of the rock layer,and the elastic modulus is negatively correlated;and the soft and hard layers of different layer thickness and different layer thickness rock masses are penetrated and destroyed.(2)The physical model test results of the tunnel passing through the soft and hard interbedding show that when the tunnel passes through the soft and hard interbedding,the layer thickness ratio and the layer thickness of the rock are positively correlated with the ultimate bearing capacity,and the failure cracks appear at the arches on both sides of the tunnel portal.(3)The numerical simulation study on the stability of surrounding rock in the excavation process of soft hard interbedded tunnel with different layer thickness ratio shows that when the layer thickness ratio decreases,the greater the stress concentration on both sides of the tunnel,the greater the tunnel displacement,and the plastic zone appears at the arch waist on both sides of the tunnel.(4)The numerical simulation study on the stability of surrounding rock in the process of tunnel excavation with soft and hard interbedded structure with different rock layer thickness shows that with the increase of rock layer thickness,the smaller the stress concentration on both sides of the tunnel,the smaller the tunnel displacement,and the plastic zone appears at the arch waist on both sides of the tunnel.Figure [54];Table [10];reference [105]...