Study On Deformation Analysis Of Surrounding Rock Of Underground Cavern In Laminated Rock

In the geotechnical engineering, discontinuous modification question can be found everywhere, many kinds of discontinuous deformation numerical analysis methods based on the separate system model can well analyze these questions, but each method has its certain limitation.The DDA method is one of the effective methods for solving the problems of discontinuous modification.In this paper, the theory of DDA was studied in the key point and two disadvantages were found: First, each block was assumed to have constant strain; Second, virtual spring was used to settle contact problems, which led to the possible insertion among blocks. Based on these two problems studies were carried out and the multi-body FEM was put forward.The main contents can be shown as follows:(1) The basic principle of multi-body FEM was introduced in detail. Combined the theory of FEM with multi-body system dynamics ,the relative deformation of each block was calculated by FEM.the blocks were interrelated by contact force.and the deformation of each block,contact forces among blocks, whole motion of the block were considered as unknown quantities.which were governed by displacement compatibility on interface and global system balance equations. In this way, a complete set of multi-body FEM was formatted to make discontinuous deformation analysis.(2)Based on a series of assumptions, the criterion of contact problem was presented. Applied the basic principle of multi-body FEM, a program of the multi-body FEM was exploited with Fortran.The feasibility of the calculating method and the validity of the calculating program were indicated by the examples of stop logs.(3) The method of Multi-body FEM was applied in the deformation analysis of surrounding rock of underground cavern in the laminated rock. Compared with other methods adopted most presently in deformation analysis of underground cavern, the method of Multi-body FEM could better response the contact condition and contact force of the contact face,and the results made better agreement with the rule of the project real case.