UNDERSTANDING OF THE OCCURRENCE OF ROCKBURSTS IN TUNNELS BASED ON 3D STRESS ANALYSIS
Rockburst usually occurs in tunnels at depth. Some critical factors control the occurrence of rockburst, such as the in-situ stress, the strength of rock mass, the release rate of strain energy and the existing faults. So far, the analysis of rockburst occurrence has mainly concentrated on a two-dimensional stress state in tunnels. In reality, the rockburst frequency has been reported not only related to the distances to the tunnel face but also to the time interval of blasting rounds. In this paper, a 3D stress analysis has been carried out in a deeply located circular tunnel with both the Mohr-Coulomb criterion and the Hock-Brown criterion. The variation of principal stress versus the advance direction of the tunnel has been obtained. The maximum principal stress concentration occurs at about 20 m away from the heading face. It is predicted that strong rockburst may take place in the tunnel by the criteria of maximum tangential stress. After that, a case study of 3D stress analysis at the Qinling road tunnel in China has been modelled by FLAC3D. The maximum frequency of rockburst occurs neither near the tunnel heading face nor just after excavation by blasting. The delaying effect of maximum principal stress in numerical modelling is similar to the delayed effect of rockburst occurrence in the tunnel. From the 3D numerical stress analysis, the occurrence of rockburst can be better understood.
DI-YUAN LI XI-BING LI ZI-LONG ZHOU
School of Resources and Safety Engineering, Central South University, Changsha, 410083, P.R.China
国际会议
The 7th International Symposium on Rockburst and Seismicity in Mines(2009年第七届国际岩爆与微振动性学术研讨会)
大连
英文
449-456
2009-08-21（万方平台首次上网日期，不代表论文的发表时间）