PRACTICABLE BEM ANALYSIS OF FRICTIONAL BOLTS IN UNDERGROUND OPENING

In this paper, a new boundary element method for the interaction betwe en frictional bolts and rock mass is presented by formulating the surf ace frictional forces of the bolts in terms of the displacements of th e rock mass. The corresponding formulation for the underground opening s supported by frictional bolts is derived. The action of the bolts on the rock mass is reduced to line integrals along the bolt length. The n the bolts are discretized into a number of quadratic elements. Analy tical expressions are obtained when the source point coincides with on e of the element nodes. Formulations for calculating the stress at int ernal points are also presented. The algebraic equations are establish ed by the usual nodal collocation scheme. A computer code for the appr oach has been written based on the linear element program. Finally, tw o examples are presented to demonstrate the effectiveness of this meth od.