Three-dimensional numerical simulation and analysis of excavation and support in underground tunnel

With the implicit rock-bolt element adopted,the behavior of underground tunnel excavation and support is analyzed by using three-dimensional computation method,which can reflect the reinforcement effect on surrounding rock with fully-grouted bolt and shotcrete support.The principle of this method is used to establish a fully-grouted rock bolt element model which comprises rock materials and bolt materials.The implicit bolt element and spray layer element,which are implied in the rock element,could be independent of the influence of mesh division,so the mesh generation of the large scale reinforced rock structures becomes relatively convenient and feasible.With this method,the influence of rock-bolt parameters on underground cavity excavation could be effectively reflected;moreover,it is feasible to simulate the time-effect of steel framework and rock-bolt structure.Applying the method mentioned above to the practical engineering,the finite element calculation results preferably reflect the behavior of reinforcement of fractured rock mass with the support of rock bolts,shotcrete and steel framework.An efficient and quick computation method is provided for the design of underground cavity excavation and rock reinforcement.