Abstract:
Based on the typical zones of ground fissures in Xi’an, the geological mechanics model of the actual activity mode of ground fissures is established. The transfer law of formation stress and displacement under the action of active ground fissures is studied with the FLAC3D numerical simulation method. The results show that under the action of active ground fissures, the curves of ground vertical displacement exhibit an approximate reverse-S shape, indicating the phenomenon of traction deflection. The curves of horizontal displacement appear the phenomenon of an obvious peak. The vertical and horizontal displacement gradually increases with the settlement of the hanging wall of the increasing ground fissure. Based on the average ground deformation tilt values induced by ground fissures, the affected zone range of ground fissure belts is determined, which is 21 m in the hanging wall and 13 m in the football from ground fissures, respectively. The fault throw on both sides of the formation induced by ground fissures gradually decreases with the depth from deep to shallow surface, which is characterized by the obvious deformation transfer and attenuation. The curves of fault throw of formation variation with the buried depth can approximately be expressed using a quartic polynomial equation. Under the action of active ground fissures, there appears a stress reduced area in the hanging wall, which is bigger than the stress enhanced area in the footwall. The stress variation range in the hanging wall and the football gradually increase with the increasing settlement of the hanging wall. The relationship between the affected zone of the formation stress on both sides of ground fissures, which gradually increases with the increasing buried depth, and the buried depth approximately satisfies a cubic polynomial equation. The results can present a scientific basis for disaster prevention of active ground fissure zones controlled by basin faults.