Investigation of the Modelling Method of the Dam-Foundation-Reservoir System

In the dynamic FEM or FDM analysis of dam foundation reservoir system, it has been found that the solution may diverge even the traditional stability condition is satisfied in the dam, foundation, reservoir domain respectively. And it is usually difficult to evaluate the accuracy of the solutions. Such problems are investigated in the study. First, the discretization method of the system with FE or FD is investigated theoretically. It has been pointed out that the parameters such as the maximum mesh size, the time interval should be determined according to the material properties and the interested minimum natural period of the system. The stability condition defined with the mentioned parameters has been given which should be satisfied besides the traditional one introduced from uniform medium. Moreover, a method has been given out with it the mesh sizes of the zones near the interface of dam reservoir and that of dam foundation could be adjusted according to the relation of their material properties in order for vibrating waves to pass through the interfaces without distortion. Based on such investigation a systems approach for proceeding dynamic analysis is proposed for any given computing environment, accuracy requirement, and other conditions. Then, a numerical experiment has been done with an ideal 3D elastic model for testing the above proposals, and the experiment verified the theoretical results. It is expected that this paper is informative to the dynamic analysis of the dam – foundation – reservoir system.