Study On Anchorage Parameter Optimization And Supporting Effect Based On In-situ Monitoring

There are many instability accidents in large-scaled underground hydropower station project, and the mostly direct reason is that the supporting measures are improper or inadequate.Therefore, the study of the supporting system of underground caverns and the optimization of the anchorage parameters can not only provide some proposal for underground cavern excavation project, but also enhance the supporting effect, which is significantly meaningful to the prevention of engineering accidents. However, there are few actual outcomes in the study of supporting system and the optimization of its anchorage parameters.Relying on the project of underground powerhouse excavation of Changheba in Chendu, and through monitoring data research, back analys is and numerical simulation, the study of anchorage parameters optimization and its supporting effect is carried out in this paper. And the point of innovation lies in the study of the effects of anchorage parameters on the forced performance of supporting system and rock mass, and based on that the parameters are optimized. The main contects of this paper are as follows:(1) By estabilishing the 2-dimensional plane strain model of Changheba hydropower station and analyzing the in-situ monitoring data, combined with optimized algorithm, back analys is is taken out and the equivalent mechanical parameters of the rock mass in typical excavation step is obtained.(2) Based on the results of the back analys is, the pre-stress of the anchor rope and the size parameters of the bolt are optimized by numerical simulation, and the result showed that the optimized supporting system can decrease the displacement of the rock mass effectively.(3) According to the mechanical parameters from back analysis and the optimization results, a 3-dimensional numerical model of Changheba hydropower station is estabilished to simulate the whole process of cavern excavation and supporting. The result showed that the supporting effect is good in general, but the supporting measures in cross-site of the caverns need to be enhanced.