RESPONSE CHARACTERISTICS OF DIFFERENT BEDDING PLANE ANGLES TO DEFORMATION OF SURROUNDING ROCK IN LAYERED ROCK TUNNEL

There are many layer composite rock masses in tunnel engineering. The weakness of the bedding plane directly determines the stability of the tunnel surrounding rock. In order to reveal the influence of the bedding plane on the deformation of surrounding rock,a tunnel cross-section is established by using AutoCAD software. By importing it into the finite element simulation software ABAQUS,and embedding 0 thickness cohesive elements with different angles as the bedding plane,the tunnel section models with different bedding planes are constructed. Based on the numerical model,the response characteristics of bedding plane angle in the surrounding rock deformation are studied. It is found that the deformed region of the surrounding rock changes from the top to the sidewall during the transition from the horizontal bedding to the vertical bedding. Combined with the acoustic emission simulation data obtained by secondary development,the easy fracture zone of surrounding rock under different bedding plane angles is obtained. According to the regional distribution characteristics,3D laser scanning technology can be used to generate point cloud data for 3D reconstruction of tunnel sections after tunnel construction. In order to avoid the disadvantage of a large amount of point cloud data,the idea of hierarchical resampling is introduced to refine the local point cloud in the deformable zone of the layered surrounding rock. Through the real-time comparative analysis of the point cloud model in the deformation area of the tunnel section,the efficient and accurate monitoring of tunnel surrounding rock can be realized,which can guide the safe and stable operation of tunnel surrounding rock.