Abstract:In the concrete dam body and foundation system,there are interactions between human being¢s activity,rock¢s stress and seepage of groundwater,which are called crossfeed. Aiming at the shortcoming of the typical contact mechanics in which the contact surface is considered to be smooth,with the help of the Hertz contact mechanics and elastoplastic theory,the variation of the contact area is considered between the dam body and dam foundation under the loads. With the rock hydrology theory,the crossfeed model including the seepage field and the stress field of the dam body and dam foundation system is set up. Finally the program of the corssfeed model based on the genetic algorithm is developed,which is used to calculate a concrete gravity dam.