Research on seepage of large foundation pit excavation of a hydro-junction power plant

Seepage problem,especially involves free surface or saturation line,is a major and difficult problem in rock and soil engineering. Borrowing ideas of seepage analysis methods from sandy soil dam,and using classical subsection-combination method,simplified model I is obtained for analyzing seepage of foundation pit. Considering the effect of soil strata and using seepage refraction at the interface between two different soils,model II is obtained on the basis of model I. Seepage discharge is calculated respectively by solving the two models under the condition of normal and maximum water levels. Then comparing it with actual seepage discharge,discovered that the result of model II is better than that of model I in the condition of normal water level; and the seepage discharges of two models are less than that in engineering in the condition of maximum water level because of ignoring the impediment effect of cofferdam on groundwater.