THREE DIMENSIONAL COMPOSITE ELEMENT METHOD FOR DISCONTINUUM AND ITS APPLICATION

摘要

It is a significant issue to simulate the three dimensional complicated discontinuous rock mass by numerical method in engineering practices. The algorithm developed on the concept of composite element method (CEM) has the capability to consider conveniently discontinuity of various size, orientation, and spacing with discontinuity segments in element. In this way the discontinuities can be simulated explicitly without special elements deployed along the discontinuities. To validate the principle and program, simple examples containing joints of different orientation or number are illustrated. The computation results of the simple examples by CEM are identical with analytic solution. Then the new method is tried to be applied on the excavation of a large-scale underground power station with complicated adjacent rock. The displacement and stress when all excavation is completed are shown, which are in accordance with the general law. Some abnormal displacements reveal that because of large horizontal ground compressive stress, rock burst may occur at two rock wedges which are formed with the wall surface and faults during excavating. Both the simple and the complicated examples show the feasibility and efficiency of the proposed composite element method.