The Spatiotemporal Distribution Law of Microseismic Events and Rockburst Characteristics of the Deeply Buried Tunnel Group

Energies

Jiasong Yang¹  Jianchun Sun²  Heng Zhang²  Shougen Chen²  Liang Chen³ 

[1] China Railway No. 2 Engineering Group Co., Ltd., Chengdu 610032, China;Key Laboratory of Transportation Tunnel Engineering, Ministry of Education,Southwest Jiaotong University, Chengdu 610031, China;School of civil engineering, Changsha University of Science and Technology, Changsha 410076, China;

关键词: deeply buried tunnel;    rockburst characteristics;    microseismic monitoring;    spatiotemporal distribution;    size effect of excavation section;   

DOI  :  10.3390/en11123257

来源: DOAJ

【 摘 要 】

Rockburst disaster is one of the prominent problems faced by deep underground engineering. Microseismic (MS) monitoring techniques can be used to warn of rockburst in tunnels to provide scientific basis for rock burst prevention and control measures. Described in this paper, is an MS monitoring system based on MS source location with hierarchical strategy implemented in the tunnel group of the Jinping II hydropower station in Sichuan Province, China. The spatiotemporal distribution of MS events was analyzed in the construction process and the size effect of rockburst risk discussed by statistical analysis and numerical calculation of rockburst in seven tunnels. The results show that the active period of microseisms and the high-incidence period of rockburst are within 1.5 h after the rock disturbance. The MS events within 1D from the tunnel wall are the most intensive and are mainly concentrated near the heading face, the side wall, and the left spandrel. At the construction site, the accuracy rate of rockburst prediction is 61.8%, of which the accuracy rate of the medium and strong rockburst is 80.3%. Based on field statistics of rockburst, the increase of the tunnel excavation section size can reduce the rockburst strength to a certain extent, which is consistent with the numerical simulation results.

【 授权许可】

Unknown