【摘要】 崩塌是地震诱发的最严重次生地质灾害之一,但目前有关地震崩塌的力学机理还不清晰。为此,基于天然危岩体的宏观结构特征,从岩石断裂力学的角度入手,对比分析了不同震波模式下裂缝的失稳扩展条件,确立了拉剪破坏的危岩失稳机制;继而以能量法为手段,研究了震波能量在危岩体中的输入和耗散机制,解析拉剪条件下裂缝的扩展方向和危岩失稳机理,给出裂缝扩展的加速度临界值ac和扩展量的计算方法;最后,通过具体算例验证了模型的合理性;结果显示,震时危岩体的失稳是裂缝在拉剪震波作用下沿震波入射垂直方向间断扩展累积的结果。更多还原

【Abstract】 As one of the most serious hazards in an earthquake,the collapse is very hard to control largely because the failure mechanism of rock slope is not clearly addressed.Here from the view of Fracture Mechanics and based on the structural characters of natural dangerous rock,the propagation condition of cracks under different seismic waves was analyzed contrastively,and it is found that the tension-shear failure of cracks is the main mode of collapse in an earthquake.Then the energy method was taken as a main way to study the crack propagation direction and rock failure mechanism.The paper proposed approaches to calculate the crack growth amount and critical seismic acceleration,which result in crack failure.Finally,an example was given to validate the theory.The result shows the failure of dangerous rock in earthquake is mainly caused by the discontinuous propagation and continuous accumulation of cracks under tension-shear action of seismic action and along the vertical direction of seismic force.更多还原