Mechanism and Catastrophe Theory Analysis of Circular Tunnel Rockburst
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摘要: 硐室岩爆机制是围岩中处于极限状态的塑性变形集中区承载能力下降时，其中完好岩体部分以弹性方式卸载，当后者释放的弹性能超过前者形变耗散的能量时便发生岩爆．以岩体等效应变为状态变量，建立了硐室岩爆的突变模型，给出岩爆释放地震能计算式．分析表明: 岩爆发生条件与岩体的升降模量比及岩体裂隙发育程度有关；对于特定冲击倾向的岩体，存在相应的临界软化区深度，当满足岩爆发生条件，且软化区深度达到临界深度时会发生岩爆．Abstract: Mechanism of circular tunnel rockburst is that,when the carrying capacity of the centralized zone of plastic deformation in limiting state reduces,the comparatively intact part in rock mass unloads by way of elasticity;rockburst occurs immediately when the elastic energy released by the comparatively intact part exceeds the energy dissipated by plastic deformation.The equivalent strain was taken as a state variable to establish a catastrophe model of tunnel rockburst,and the computation expression of the earthquake energy released by tunnel rockburst was given.The analysis shows that,the conditions of rockburst occurrence are relative to rock's ratio of elastic modulus to descendent modulus and crack growth degree of rocks;to rock mass with specific rockburst tendency,there exists a corresponding critical depth of softened zone,and rockburst occurs when the depth of softened zone reaches critical depth of softened zone.
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