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地震荷载作用下边坡失稳判据是岩土力学研究的热点和难点,综合运用极限分析和波动理论,从功率角度出发,提出外力功率等于内能耗散的岩质边坡能量稳定性评价方法。借助强度折减法和超载系数法,通过安全系数对单节理边坡进行定量化安全性评估。以P波倾斜入射单节理边坡为例,首先,研究边坡的自稳临界高度和应力波入射节理透反射基本规律;其次,在边坡临界自稳高度范围内,研究应力波作用下边坡临界高度的动态变化情况;最后,根据外力功率等于内能耗散的判断准则,通过强度折减法和超载系数法,分析动荷载作用下单节理边坡动态安全系数的变化,计算块体极限滑动时所需的能量。研究表明:边坡节理面的黏聚力越高,其自稳临界高度越高,动荷载作用下边坡动态临界高度也越高,抗震性能也越好;随着入射P波峰值强度的增大,边坡动态临界高度降低的幅度也增大;随着入射角度的不断减小,边坡动态临界高度变化的幅度不断增大,表明地震作用下边坡破坏的可能性不断增大;边坡动安全系数的变化趋势与透射应力的变化趋势相反;边坡的高度越高,块体越不稳定,其极限滑动时所需的能量也越少。
Under the action of seismic load, the criterion of slope instability is a hot and difficult point in the research of geomechanics. Based on the limit analysis and the wave theory, from the power point of view, the method of evaluating the energy stability of rock slope is proposed, in which the external power is equal to the internal energy dissipation . With the strength reduction method and overload coefficient method, the safety factor is used to evaluate the safety of single joint slope. Taking P-wave inclined incident single joint slope as an example, firstly, the critical height of self-steady slope and the fundamental law of incident reflection of stress wave are studied. Secondly, within the critical self-stability height of slope, Finally, according to the judgment criterion that the external power is equal to the internal energy dissipation, the change of dynamic safety factor of single joint slope under dynamic load is analyzed by strength reduction method and overload coefficient method, and the limit slip of block When the required energy. The results show that the higher the critical height of self-stability is, the higher the dynamic critical height of slope is and the better the anti-seismic performance is. As the peak intensity of incident P-wave increases The magnitude of the dynamic critical height decrease also increases. With the decrease of the incident angle, the dynamic critical height of the slope changes continuously, which indicates that the probability of the slope failure is increasing under the action of the earthquake. The change trend of safety factor is opposite to the change trend of transmission stress. The higher the height of slope, the more unstable the block, the less energy it needs when it slides.