地震作用下结构失稳诱发的塌陷和地裂缝机理分析

Analysis on Mechanism of Collapse and Ground Fissure Caused by Structure Instability under Seismic Action

分析了地震诱发的地表塌陷和地裂缝机制。通过地裂缝微观机理分析研究发现:(1)地震造成了大量的地裂缝和塌陷,这些破坏的出现与地震发生时造成的瞬间应力变化和结构破坏密切相关;(2)利用结构突变失稳理论来研究岩土体内部结构是可行的。当应力状态满足孔隙结构失稳判别式时,结构元的变形状态将产生一个“跳跃”;(3)地震情况下岩土体颗粒之间有效接触力的增加,使得结构的变形能增大;同时导致颗粒间连接刚度的降低,导致结构的失稳,这些变化又是在瞬间发生和完成的,这就造成了在地震发生时总是伴随着大量的裂缝和塌陷的出现。

The mechanism of ground collapse and fissures caused earthquake is analysed in this paper. The study of the micro-mechanism of the ground fissure shows that earthquakes have resulted in a lot of ground fissures and collapses. These destructions are closely related to instantaneous stress change and structure damage. It is feasible to study the internal structure of rock and soil mass by using the theory of abrupt structure destabilization. When state of stress satisfies discriminant of interstitial structure instability, structure deformation will cause a bounce. In case of an earthquake, an increasing strength between grains of rocks and soil mass can augment deformation energy of the structure and reduce the rigid degree of joint grains and leads to structure instability. So, these instant changes always result in a great lot of ground fissures and collapses during earthquake.