Seepage is always a difficult point and a hot topic. In recent years

some scholars have put forward calculation methods of earth pressure and water pressure(called convention methods) on retaining structure with seepage based on their research findings. In addition

the finite element program PLAXIS can calculate earth pressure and water pressure on retaining structure through seepage flow-strain coupling. The article compares calculation results between convention methods and PLAXIS

then finds there are definite errors in calculation results because their assumptions differ from the fact. And the article analyses applied condition of invention methods and points out that earth pressure and water pressue with PLAXIS are appropriate and believable under true waterpower conditions.