Analysis of rock burst and crustal stress measurement in a hydropower’s traffic tunnel at ganzi prefecture, Sichuan Province

摘要

There was a hydropower in the transition zone between Qinghai-Tibet plateau and Sichuan Basin, while excavating the traffic tunnel towards its underground structure at about 631 m horizontal depth, many rock burst happened at right arch, and the hydraulic fracturing three dimensional stress measurement was adopt at the place immediately. The paper introduced the process and the result of this measurement, analyzed the spatial distribution of crustal stress and the maximum tangential stress σθ max in tunnel excavation. It found that the direct mechanical cause of the rock burst was that the σθ max at the site of right arch reached 39 MPa, which have greatly exceeded the rock burst critical stress σ lcr 29 MPa.