Practicable BEM Analysis of Frictional Bolts in Underground Opening

Abstract

In this paper, a new boundary element method for the interaction between frictional bolts and rock mass is presented by formulating the surface frictional forces of the bolts in terms of the displacements of the rock mass. The corresponding formulation for the underground openings supported by frictional bolts is derived. The action of the bolts on the rock mass is reduced to line integrals along the bolt length. Then the bolts are discretized into a number of quadratic elements. Analytical expressions are obtained when the source point coincides with one of the element nodes. Formulations for calculating the stress at internal points are also presented. The algebraic equations are established by the usual nodal collocation scheme. A computer code for the approach has been written based on the linear element program. Finally, two examples are presented to demonstrate the effectiveness of this method.