Advances in Earth Science ›› 2008, Vol. 23 ›› Issue (5): 482-487. doi: 10.11867/j.issn.1001-8166.2008.05.0482

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Study on Surrounding Rock Quality Classification Motheds in High Primary Stress Condition

Zhao Qihua 1,Chen Jinzhong 2,Peng Sheqin 1   

  1. 1.State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology , Chengdu 610059,China; 2.Sichuan Institute of Geological Engineer Explore, Chengdu 610072,China
  • Received:2008-04-12 Revised:2008-04-14 Online:2008-05-10 Published:2008-05-10

Zhao Qihua,Chen Jinzhong,Peng Sheqin. Study on Surrounding Rock Quality Classification Motheds in High Primary Stress Condition[J]. Advances in Earth Science, 2008, 23(5): 482-487.

Surrounding rock quality classification is one of the professional key works in tunneling and underground engineering. So far, the popular methods of surrounding rock quality classification might suitable for the mid-lower or lower primary stress, but nearly useless in high primary stress condition, because of cases shortage. Based on an hydraulic power engineering in high primary stress case, this paper use classification methods BQ, HC, RMR and Q system in turn to determine the quality grade of surrounding rock. The coherence and difference of above four classification result was deeply studied by contrasting and reason analyzing. And an important fact was found that classification rule and its index or weight for every index all had notable difference in above four classification methods. So, the classification methods Q system, HC, RMR at present had been modified one by one according to high primary stress environment and rock-burst. For Q system, primary stress reduction factor, joint roughness coefficient Jr and joint weathering and erode coefficient Ja had been mainly modified. For HC classification method, considering the influence of high primary stress and rock-burst, propose primary stress reduction factor K, cancel the index of ratio of strength and stress S. For RMR classification method,the index of R6 was mainly modified, at the same time, primary stress reduction coefficient was added. The classification result was much more accordant to the matter of fact after being modified. In the end, based on probability and statistical theory, general classification scheme was put forward. 

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