摘要：Reservoir impoundment is related to several hydraulic engineering concerns,including irreversible valley contractions,landslides and reservoir-induced ***,these phenomena,such as valley contractions,are hardly to be explained by the conventional *** scientific understanding of water effects during impoundment and their hazards to hydraulic structure are *** effective stress law for fissured rock masses is introduced in the elasto-plastic model employing the Drucker-Prager criterion and implemented in the three dimension(3D)nonlinear finite element method(fem)program Three-dimensional FINite Element(TFINE).The slope deforms towards river-way during impoundment since the increasing pore pressure in fissures changes stress state and leads to additional plastic deformation in the rock *** value of Biot coefficient and the influence of water on rock materials are discussed in ***,the mechanism of slope deformation during the impoundment of Jinping-I arch dam is revealed,and the deformation is accurately *** application of the effective stress law provides a method to consider stress assessment,deformation evaluation and stability estimate of hydraulic structures during the impoundment *** is a beneficial exploration and an improvement of hydraulic engineering design.