An empirical investigation into the effects of mine induced stress change on standard cable bolt capacity.

摘要

Laboratory pull tests were performed with a Modified Hoek Cell and tests were conducted at constant confining pressures and different water:cement ratio grouts (0.3, 0.4 and 0.5). The results indicate that confining pressure does play a significant role in controlling cable capacity, in particular higher radial confining pressures produce higher cable capacities. Confining pressure is dependent on grout quality and radial stiffness of the bore hole. The confining pressure acting on the cable/grout system, and therefore the cable capacity, can be influenced directly by mining induced stress changes and by stress induced changes in radial stiffness.;A methodology for the analysis of failed cable bolted ground is described. This provides a logical approach for determining those factors which may have contributed to the failure. The methodology outlines controlling factors governing cable bolt capacity and utilizes these with a performance assessment chart. (Abstract shortened by UMI.).;An empirical model was developed from the laboratory results which enables the cable capacity to be determined for a standard cable installed in 0.3 w:c grout with 250mm of embedment length and in any type of boundary condition. This is the first empirical constitutive model that enables analysis of confining pressure changes at any time prior to or after ultimate cable capacity has been attained. Other models only consider ultimate load and stress change effects after ultimate load has been reached.