Abstract:

The effect of pumping on ground fissures caused by fault is obvious, but its mechanism is rather complicated. Most of the previous corresponding researches are simple qualitative analysis, while numerical simulation and quantitative analysis are few. A new method was adopted to simulate the fault effect on ground fissures during pumping, which is based on Biot seepage and consolidation theory and contact surface element considering the contact relationship of side A and B. The results indicate that pumping could arouse stress change around pumping well, the horizontal earth stress near the well ascend while descend far away from it, causing cracks come into being from above to below when horizontal stress exceed the tensile strength. Additionally, preexisting fault affect the stress redistribution distinctly. Due to the low strength of fault surface, it is easy for stratum to be tore apart or slide along the fault, promoting the activity of ground fissures. In general, the effect of preexisting fault on ground subsidence and fissures includes induction, segregation and amplification.

Key words: pumping action, preexisting fault, ground fissures, numerical simulation, groundwater