| The stability of tunnel surrounding rock is an important research topic in geotechnical engineering,which has important guiding significance for geological advance prediction,engineering design and monitoring.This paper focused on the fracture of rock structure face to the influence of the stability of surrounding rock,using theoretical analysis,laboratory test and numerical simulation method to study the rock sample micro crack propagation and fracture and fault structure in the face of the influence law of surrounding rock damage,and take the horse home kiln tunnel as an example,studied the joint fissure,fault the influence law of the deformation of surrounding rock of the tunnel,The main conclusions are as follows:(1)The range of deformation and failure of the model specimen is controlled by the inclination angle of the crack structure.The total number of microcracks,the axial stress and the crack length are positively correlated to a certain extent,and the elastic modulus and deformation modulus of the specimen are negatively correlated with the total number of cracks.(2)The inclination angle and length of the fracture surface will have different effects on the different damaged areas of the tunnel and the degree of damage.The increase of the inclination angle of the crack structure will cause the damaged area of the tunnel to gradually move from the shoulder area of the tunnel to the waist area of the tunnel and the arch bottom area;as the length of the crack decreases,the total number of microcracks and the axial stress decrease.;As the distance between the crack and the tunnel increases,the interaction force between the crack and the tunnel is gradually weakened.(3)The subsidence of the vault,the uplift of the inverted arch and the extent of the tunnel failure of the Majiayao tunnel are controlled by the width of the fault fracture zone,the dip angle of the fault plane and the distance between the fault and the tunnel.The inclination angle of the fault structure plane is negatively correlated with the subsidence of the tunnel vault and the uplift of the inverted arch,and the abrupt change between the subsidence and the uplift is also decreasing.The value is positively correlated,and the abrupt change between subsidence and uplift is also increasing;the angle between fault strike and tunnel axis,and the maximum value of tunnel vault settlement and inverted arch uplift are positively correlated,but the subsidence abrupt region increases first.Large and then reduced.(4)Through the study of different grouting support thicknesses,the stability of fault surrounding rock can be significantly improved by grouting support within the intersection area of fault and tunnel.It is suggested that the support thickness of Majiayao tunnel should be 0.3 times of the long axis radius of the tunnel to ensure the safety of the tunnel and improve the economic benefits.There are 57 figures,7 tables and 64 references. |
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