Study on the Anisotropy of Fractured Rock Mass under Unloading Effect

摘要

Mechanical property of cracks in the excavation process under unloading effect is one of the main issues of unloading rock mass mechanics.In this paper,finite element was used to simulate the anisotropy of fracture and unloading rock mass;all the designed size of specimens is 3mx3m,and the angles between cracks and vertical directions are designed to 0°,8,o36o,52o,82o,90°.The paper also analyzed the calculated results,and obtained the variation law of mechanical properties of the same scale fractured rock when changing with the direction of fracture:first,the orientation of structural plane has a direct impact on the characteristic of unloading when unloading;second,the tensile strength when unloading to damage decreases with the angle of the structural plane;third,the tensile deformation modulus of rock mass decreases significantly with the angle of structural plane,and the compression deformation modulus decreases with it when beginning,but increases with it when the angle of structural plane increases to a certain extent;fourth,the anisotropy of unloading rock mass not only exists in intensity,but also in deformation.