Únosnost tmelených horninových svorníků

Abstract

The diploma thesis focuses on bearing capacity of passive bonded rock bolts (dowels). It points out possible ways of losing the bearing capacity and introduces types of cracks and their spreading, which are formed by pulling the bolt in close vicinity to the bolt-grout contact area. Failure at bolt-grout interface is investigated in more detail with respect to effect of ribs. Ribs generally increase shearing capacity at the interface but they also cause stress concentrations and the associated development of cracks. Laboratory rock bolt pull-out tests have been carried out in order to simulate stress distribution in anchor length of the rock bolt. The pull-out tests have been conducted on rebar, grouted into concrete with cement mortar. Stress-strain dependence of rebar and rock bolts of two different anchor lengths are the outputs of the practical part. Laboratory test has been simulated by numerical modeling FEM in software Plaxis 2D axisymmetry and in software Midas GTS 3D in order to evaluate stress-strain state before failure and progress of displacements along anchor length.