强余震的断裂力学机理

DISCUSSION OF A KIND OF STRONG AFTERSHOCKS OCCURRING BASED ON FRACTURE MECHANICS

摘要:

利用应变能密度理论,结合裂纹闭合的作用,研究混合型裂纹的扩展。在考虑裂纹闭合的影响时,我们仿照Mclintock和Walsh^[1](1962)的思路,研究直的裂纹。

Abstract:

Based on the strain energy density theory on the unstable growth of mixed mode cracks, this paper discusses some problems on fracture law and activity characteristics of strong aftershocks occured at the end of main fracture of large earthquakes. Combining some relative examples, it suggested: 1. the angle between fracture planes of this strong aftershock and its main earthquake should be much more than zero degree; 2. this strong aftershock should generally locate at the corner of attenuation curve of aftershock frequence; 3. the relationship between fracture length and magnitude of strong earthquakes is quite close to the result obtained by Guo Zeng-jian and others. 4. the growth length is about 0.16 time that of main fracture.