The Effect Of Groundwater On Surface Ground Motion Parameters

The research about the effects of site conditions on earthquake damages and ground motion parameters has been one of the hot problems in the study of geological engineering seismic resistance. Groundwater, as one of the important site conditions, has been proved to have a significant influence on seismic intensity and other parameters by the results of earthquake damage investigation. The soil below the water table, which should be considered as two-phase medium, has some certain complex effects on numerical simulation, so the study about the effects of groundwater on the ground motion parameters is still in the state of development. Based on the research results, the paper compared several existing volatility models of two-phase medium, and introduced Biot’s model to the analysis of soil layers seismic response, which presented a method for soil layer seismic response analysis of considering two-phase medium, and verified by contrasting the array records of Xiangtang array in Tangshan. In this paper, the effects of groundwater on the ground motion parameters were calculated, and some meaningful conclusions were also obtained. The paper mainly completed the following works:1. This paper briefly summarized the progress of the study that the influence of groundwater in intensity and ground motion parameters, and reviewed the main achievements of the study. It also compared and analyzed four kinds of two-phase medium wave modes and their strong and weak points and their applicability, and the current study of numerical simulation of two-phase medium wave were also introduced.2.In this paper, the Biot’s wave equation was discretized by the staggered grid difference algorithm, and exported the difference scheme of numerical simulation. A method for seismic response analysis of soil layer considering saturated two-phase medium was proposed by using the staggered grid finite difference algorithm and the artificial transmission boundary. The soil seismic response of the 3# logging in Xiangtang array was calculated by using the method. By comparing with the actual earthquake records, the rationality of this method was verified.3. The effects of groundwater and groundwater depth on ground motion parameters, such as the peak ground acceleration and platform value of response spectrum, were calculated and analyzed, and some meaningful conclusions are obtained.