Abstract: In order to study evolution characteristics of strata deformation under influence of construction disturbance and heavy rainfall infiltration, simulation research was conducted on features of surface subsidence under different rainfall intensity and excavation depth by using universal distinct element code (UDEC). Then, distribution law of surface pore water pressure and displacement field during excavation was explored. The results show that along with the increase of excavation depth, pore water pressure decreases gradually while settlement of soil layer increases obviously, both of which are affected by distance between monitoring point and excavation position. Soil settlement, in the event of rainfall, is easily affected by excavation conditions as settlement of soil near upper layer (such as mixed fill and gravel fill, clayey soil and sand etc.) is similar after excavation, and that of lower soil (such as structural fracture zone) is relatively small. It is also found that rainfall infiltration increases settlement of upper soil which features loose properties, good permeability and greater deformation characteristics.

Key words: excavation depth, pore water pressure, rainfall intensity, soil characteristic, settlement