There are many coupling effects in rock and soil engineering; seepage field and stress coupling is important in the water resources and hydropower engineering. Taking a hydraulic project foundation pit excavation as engineering background

Biot’s consolidation theory as theoretical basis

and Mohr-Coulomb’s principle as soil yield criterion

hydro-mechanical coupling of foundation pit is simulated in the process of excavation. The results indicate that the stress of backfill is larger than that of excavation

and there is a certain degree stress concentration near the open caisson. There is little yield region before and after backfill; so yield failure of soil is not a major problem in the engineering. Because of large coefficient of permeability of soil and high level of groundwater in the region of powerhouse

seepage discharge is very large in the process of excavation. Open caisson and impervious soleplate laid on the floor of the foundation pit have obvious effect on reducing seepage discharge. In conclusion

permeability-reducing and drainage are the key problem in the process of excavation of the engineering.