Evaluation of support characteristics of wet-mixed shotcrete with powder type cement mineral accelerator

摘要

Instead of conventional in situ cast concrete lining, permanent shotcrete lining is widely used. In order to secure the required performance of the shotcrete, elements such as the strength, deformability, durability, pumpability and rebound ratio are of great importance. In this study, the mechanical performance of high-strength shotcrete (wet-mixed shotcrete with powder type cement mineral accelerator) at the weathered rock condition was evaluated. In the performance analysis, the finite difference method (FLAC by Itasca) was used. The factor of safety of shotcrete lining against flexure was examined. When using the high-strength shotcrete, the factor of safety increased by a small amount. For the same factor of safety, however, the thickness of shotcrete could be remarkably reduced. In addition, the ground reaction curve analysis was carried out to examine the amount of displacement and time for the convergence. The ground reaction curves calculated by the finite difference method well explained the real ground behaviour and well suited with theoretically obtained curves.