Abstract：A new element form，which is based on the displacement interpolation function of triangular or quadrangular solid element and the stiffness matrix of one-dimensional truss element，is introduced into the analysis on bolt-reinforced underground structure. By using the new developed method，the bolt can be freely added or removed at the arbitrary excavation step in the finite element analysis of underground structure，and the bolt nodes need not be previously considered or arranged in the mesh generation procedure，so that the work of pre-process or mesh division procedure in finite element method can also be much reduced.
