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岩爆作为深埋地下工程围岩的一种破坏方式,其发生条件受多种因素的制约。根据在锦屏二级深埋隧洞掘进过程中的岩爆统计结果,即使应力条件和岩体强度达到一定的要求,岩爆发生与否以及剧烈程度还与岩体力学特性有密切的联系。锦屏二级深埋隧洞沿线以大理岩为主,为此开展了大理岩力学特性与岩爆发生关系的相关研究工作。根据大理岩三轴压缩试验结果,验证了大理岩的脆-延-塑转化特性,确定了锦屏白山组大理岩的转化围压和相关的Hoek-Brown强度参数,并利用经验的方法初步评价了锦屏深埋大理岩的岩爆风险。为了进一步明确岩体力学特性对岩爆风险的影响,利用现场实际的岩爆破坏形态,通过考察不同深度处测点的应力路径,校核了现场岩体的力学参数。在此基础上分析了具有岩爆风险的围岩力学状态,分别研究了岩石强度、岩体完整性和岩体脆性特征对岩爆发生条件的影响。研究结果表明,锦屏大理岩岩石强度和脆性特征可以影响到锦屏深埋隧洞围岩岩爆风险程度,但其影响相对较小,而岩体完整性对岩爆风险形成具有比较明显的影响。
Rock burst as a method of destruction of the surrounding rock in deep underground engineering, the occurrence of conditions by a variety of factors. According to the rockburst statistics during the tunneling of Jinping No.2 deep tunnel, even if the stress conditions and rock mass strength reach certain requirements, the occurrence and severity of rock burst and rock mechanics are closely linked with the mechanical characteristics of the rock mass. The main Jinping second-level deep-buried tunnel is dominated by marble, so the relevant research on the relationship between the mechanical properties of marble and rockburst is carried out. According to the results of triaxial compression tests of marble, the brittle-ductile-plastic transition characteristics of marble are validated, the confining pressure and the related Hoek-Brown strength parameters of marble in Jinbaibaishan Formation are determined, and preliminary evaluation is made by empirical methods Jinping buried rock deep rock burst risk. In order to further clarify the influence of mechanical properties of rock mass on the risk of rock burst, the actual rock burst morphology was used to study the mechanical parameters of on-site rock mass by investigating the stress paths of measuring points at different depths. On this basis, the mechanical state of surrounding rock with rock burst risk is analyzed, and the influence of rock strength, rock mass integrity and brittleness of rock mass on rock burst conditions are studied respectively. The results show that the strength and brittleness of marble in Jinping marble can affect the rock burst risk of surrounding rock in Jinping buried tunnel, but its influence is relatively small, and the integrity of rock mass has a significant impact on the rock burst risk formation .