【摘要】 将围岩看成弹性体,断层看成具有应变软化的弹塑性体,断层和围岩组成统一的地质介质系统。在给定的地应力、孔隙压力及边界位移的作用下,应力逐渐积累,当达到断层强度时,断层进入塑性状态,应变随之软化,应力突然下降,能量突然释放,形成地震。根据这个原理,利用有限差分FLAC软件,对汶川5.12地震的机理进行了模拟。模拟结果证实:汶川5.12地震是在青藏高原侧向挤压,四川盆地阻挡,使龙门山断裂带受到缓慢增加的挤压应力场作用下形成的。计算结果给出了应力降、能量释放量、断层错动量、地震同震位移、震前位移、地震复发周期等重要参数,结果与野外调查及其它资料给出的数据具有较好的一致性。更多还原

【Abstract】 In this paper,strain softening model is used for modeling the Wenchuan earthquake.Results shows that this earthquake was caused by compressing of Qinghai-Tibet Plateau and block of Sichuan Basin.The stress drop,energy release amount,the magnitude of dislocation of fault,coseismic displacement,displacement before earthquake and earthquake recurrence intervals are given by the modeling.The modeling results are in good agreement with geologic and geomorphologic survey and others data.更多还原