The Effect Of Soil Damage Under Wenchuan Strong Earthquakes Area

Wenchuan earthquake which damaged severely the both sides of the slope beside the Duwen roads and resulted in a large number of landslides, caused heavy losses to people's lives and property. Therefore, landslide control to ensure road safety has an important value of the works, not only to provide engineering design basis to landslide control, but also to avoid the dammed lake which was caused by the landslide avalanche to the surrounding watershed. To determine the scope of soil disturbance and the degree of soil damage by earthquakes has important basis to predict the evolution of mountain post-earthquake hazard trends as well as road repair and reinforcement works.This paper preliminary researched the soil damage and the cumulative displacement of slope under seismic action in Wenchuan strong earthquake area as well as the dynamic magnification factor of seismic wave.The soil damage of Wenchuan strong earthquake area mainly manifested in soil materials of which the strength reduced in earthquake and the soil deformation such as landslides.This article from both aspects the soil material and soil deformation to study the soil deformation effects in Wenchuan strong earthquake area in order to provide engineering control measures for road subgrade and slope (landslide).In the aspect of soil materials, research methods are surface wave test, shaking table test and numerical simulation. We obtained the velocity changes of shear wave of soil to assess the depth of soil damage mainly through surface wave test because surface wave survey is a quick means to obtain shear wave velocity changes to infer the scope of soil disturbance.In the second chapter of this paper, we will introduce the high-precision surface-wave shallow seismic exploration of six sites respectively located in two slope construction points and three embankment construction points aside the Duwen segment of National Highway 213 in strong earthquake zones, the following test results are obtained:(1)The disturbance depth of the soil inâ…¨andâ…©seismic intensity area is no significant difference; (2) In the Wenchuan strong earthquake zones, the soil disturbance depth of manual filling of the embankment projects has occured more than or equal to 5m, while the natural soil of slope is less than or equal to 5m; (3) Between filling and diging section in the surface of the embankment construction, the junction injury is obvious. The above conclusions have important references on road rehabilitation to determine the depth of both embankment repair digging and slope reinforcement during the Wenchuan reconstruction.The chapter three found the phenomenon which acceleration amplification factor was higher in shallow soil through shaking table test which simulated the earthquake to research the relation of acceleration amplification factor of soil with height and seismic intensity. Numerical simulation based on the theory of one-dimensional layered vibration, we used sake2000 software to structure a 20m thick site to research the seismic effect under two seismic action, numerical analysis gives a specific curves of the dynamic magnification factor in relation with PGA and soil height,the conclusions was consistent with the shaking table model test.Soil slope displacement was important manifestation of soil damage, the main research methods were the landslide field investigation and the measured seismic data analysis. As the complexity and uncertainty of the soil landslide caused by moderate earthquakes or strong earthquakes, it was difficult to give a specific formula from the point of force-deformation, but it was easy to obtain co-seismic displacement formula from the regression analysis. Before giving critical acceleration of slope and the correlation coefficient among the important parameters, it was important to understand the structure of slopes and the physical parameters of mechanical components. If the related parameters were calculated, we could develop the Jibson displacement regression formula, which has relation with the earthquake magnitude, epicenter distance, critical acceleration, PGA and so on.