强震作用下山体崩塌破坏有限元分析

基于汶川大地震下,山体边坡发生大规模塌滑等地质灾害的现状,为了深入研究山体在强震动力作用下进入非线性状态并开裂破坏的力学机理,通过理论研究从拉张破裂的角度对山体崩塌机制进行分析,并给出拉张判据。用有限元开发程序对山体边坡在强震动力作用下拉张破坏进行数值模拟,并与振动平台相似材料实验下的监测结果对比分析。表明,强震荷载激励下,岩石第一主（拉）应力极易达到其抗拉强度,则岩体优先发生拉张破裂。在强震动力作用过程中,拉张破裂不断积累,即在松动区的松散程度和松散范围不断增大,形成山体塌滑趋势。揭示了山体边坡从连续介质状态开始崩塌破裂的发生机制,为后续进行复杂的山体破坏力学研究提供依据。

Numerical analysis of rock fall under strong Earthquake using finite element method

Based on the situation that geological hazards occurred,such as large-scale landslide of mountain slope,due to the Wenchuan Earthquake,and in order to further study the mechanical mechanism of mountain body entering the nonlinear state with cracking destruction under strong earthquake,we analyzed the collapse mechanism of mountain body from the perspective of tension fracture through theoretical study and the tensile fracture criterion.The finite element program is developed to simulate tensile fracture process of mountain body under strong earthquake,and the results are comparaed with the monitoring results from the similar material test by the vibration platform.The following conclusions can be drawn： the first principal（tensile）stress is greater than or equal to the tensile strength of rock easily under the motivation of strong earthquake,thuse tension fracture of rock firstly occurs;The tensile fracture region cumulates continuously during earthquake dynamic,which means the loose degree and the loose range become increase,forming a trend of collapse.It reveals the occurrence mechanism of mountain slope which begins to collapse in the state of continuous medium,and provids theoretical basis for making subsequent research on the complicated failure mechanics of mountain body.