Dynamic Analysis of Mei-Da Expressway Subgrade Slope: Under Simplified Groundwater Seepage Pressure and Vehicle Load

Under the combined action of groundwater infiltration and vehicle load, the physical and mechanical properties of highway subgrade slope have complex dynamic changes, which are easy to produce landslides and pose a serious threat to the surrounding areas. Based on the slope of a section of Mei-Da Expressway, the dynamic characteristics and influencing factors of expressway slope under groundwater seepage pressure and vehicle load were analyzed by using finite element modeling (FEM) and orthogonal test method, and the dynamic response mechanisms of slope monitoring points under six potential sliding surfaces and three seepage path angles were discussed. The results show that the variation of horizontal and vertical acceleration, velocity and displacement responses of the slope is closely related to the traffic loading, potential sliding surface and seepage path. The maximum acceleration, velocity and displacement response of the slope show a trend of “first increase and then decrease”. The horizontal and vertical change trends are different, and there is a large displacement increase proportional coefficient (DIPC) fluctuation in the middle of the slope, more attention should be paid on. From the orthogonal test of 4 factors and 3 levels, it is concluded that the influence of vehicle load factors is dominant, which is much higher than the set significance level threshold, the influence of potential sliding surface depth is second, and the influence of seepage path is the smallest. The research results can provide theoretical basis for vibration and protection design of highway subgrade slope engineering.