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针对现有岩爆研究的不足,基于突变理论建立了围岩卸荷岩爆的劈裂突变模型,得到了考虑卸荷影响的劈裂岩爆必要条件和充分条件并在此基础上进行了因素敏感性分析。研究表明,开挖卸荷致拉明显降低了突变特征值及岩爆发生的门槛,使岩爆发生的可能性大为增加,而且当拉应力σx=πσt/4时,必要条件就成为充分条件;卸荷后一段时间围岩发生变形,达到发生岩爆至少所需的卸荷细观拉应力,形成标准或滞后岩爆模式;竖向应力达到一定值,围岩卸荷瞬间其突变特征值Δ≤0,形成瞬时岩爆模式;岩爆劈裂要满足一定的临空面尺寸要求,随竖向应力的增大这种要求明显减弱;发生岩爆时岩爆区释放的能量ΔE,σx,Δ对竖向应力的敏感性很强,Δ对σ3极为敏感。
Aiming at the shortcomings of existing rockburst research, a fracturing catastrophe model of rock unloading rockburst is established based on catastrophe theory. The necessary and sufficient conditions of fractured rockburst with unloading influence are obtained. Based on this, Sensitivity analysis. The results show that the excavation unloading induced pull significantly reduces the mutation eigenvalues and rock burst threshold, the possibility of rock burst greatly increased, and when the tensile stress σx = πσt / 4, the necessary conditions become sufficient conditions After a period of unloading, the surrounding rock deforms to achieve at least the required unloading meso-tensile stress of rock burst, forming a standard or lag rock burst mode. When the vertical stress reaches a certain value, the sudden change of eigenvalue Δ≤0, and the instantaneous rockburst mode is formed. The rockburst splitting must satisfy some requirements of the size of the freeboard surface. The requirements with the increase of the vertical stress are obviously weakened. The energy released by the rockburst zone during rock burst is ΔE, σx , Δ is highly sensitive to vertical stress and Δ is extremely sensitive to σ3.