含弱层岩石破裂前兆规律的数值模拟分析  

Numerical simulation of precursory phenomenon before fracture of rocks containing incompetent layer

作　　者：梁正召[1] 唐春安[1] 杨天鸿[1] 焦明若[1] 

机构地区：[1]东北大学岩石破裂与失稳研究中心,辽宁沈阳110004

出　　处：《地震》2003年第3期65-70,共6页Earthquake

基　　金：国家重点基础研究发展规划973项目(G1998040700);国家自然科学基金(50174013)

摘　　要：利用数值模拟软件RFPA2D模拟了含断层带岩体的破裂过程及其应力、位移和声发射前兆的复杂性和规律性。模拟结果表明,应力和位移在同一点的变化情况不同,不同点在同一时刻的位移和应力也不同,应力、位移和声发射在时间和空间上的分布呈现出一系列复杂图像,但是这些复杂变化并不是随机的,都遵循相同的物理过程和一定的演化规律。应力和位移的变化量比应力和位移本身更重要,同时这些变化的大小和断层结构紧密相关,而单一物理量的异常并不一定预示着必然的破裂。A numerical code RFPA2D is used to simulate the failure process of a rock sample with fault material during compression. We select six points to monitor t he spatio-temporal distribution of stress, displacement and acoustic emission d uring fracture nucleation and failure under constant displacement load. The resu lts show that the stress and displacement of the same point at different time or different points at the same time are not the same, and stress, displacement an d AE show a series of complicated spatio-temporal images. The observed phenomen a do not occur randomly but follow some principle and physical process. From the results it is also found that the variation of displacement depended on fault s tructure closely. Stress is built up both in the strong asperities, but stress i s very lower in and adjacent to the fault. Stress and displacement change greatl y as well as acoustic emission change greatly when the sudden collapse occurs. T he simulation provides a physical model based on RFPA forecasting. Because the v ariations of displacement and stress are more important than the value of themse lves, anomaly of one physical parameter does not lead to a certain fracture.

关 键 词：含弱层岩石 破裂前兆 数值模拟 声发射 应力 位移 地震前兆 

分 类 号：P315.72[天文地球—地震学]