Silty Clay Artificial Slope Dynamic Stability Test

With the increasingly activities of human engineering, the reconstructing on natural geomorphy is also increasing. To build residential areas and lay out lifelines in topographical relief areas, many land slopes are needed to be treated and reconstructed to ensure the safety of the residents and lifelines. In recent years, the earthquakes are very active around the world. Especially, the several huge earthquakes happened in Western China which caused much damage on the land slopes and resulting in destroy a number of lifelines (roads, railways, electricity and water supply pipelines, etc.) and enormous social and economic losses. To research the stability and failure pattern of filled soil slope under vibration condition is important for not only ensuring the safety of the residents and lifelines in seismic area but also design and reinforcement of the slopes. By indoor model test, the stability and failure pattern of the soil slopes under vibration condition has been simulated.According to data analysis, some obtainments have been concluded that as follows:1) when the strength of the concrete slab is high enough, in the process of vibration acceleration increasing, the inner structure of soil in filling soil slope changes and a structure interface appears. Upper side of the interface, the density of soil descends and the soil become loosens. Lower side of the interface, the density of soil ascends and the void ratio declines. Because of the loosening in upper side soil, the concrete slab can press back the soil and make the angle of slope smaller. The whole density of the filling soil slope increases and the slope would be more stable.2) When the strength of the concrete slab is not high enough, in the process of vibration acceleration increasing, a shear crack will appears about in the middle of the concrete slab on the filling soil slope and then a landslide will shear out from the crack. The interface of the landslide is almost the same as the0change interface of density (structure interface).3) Vibration will damage filling soil slope by causing concentrated shear stress on an interface of soil structure. This kind of shear stress can make some kind of concrete slab fracture. These results can be basis for constructing failure mode of filling soil slope under seismic shake condition.4) During in the process of vibration, the soil stress in the top side of the slope is always tensile, and in the middle part of the slope, the soil stress is mainly in the condition of compression. The soil stress in the bottom of the slope waves in a small way.5) With the increasing of acceleration, the most lateral deformation happens in the middle of the slope and the second lateral deformation is on the top of the slope. The tensile cracks what happen on the top surface extend downwards and will connect with each other on an interface. The slide surface will be developed from the interface and the shear out belt will be happened in the most lateral deformation part. At last, the slope will be damaged by a landslide.6) The grading of the soil is a very important factor which impacts on the stability of soil slope during vibration. The grading of soil is also an important indicates the scale of potential landslide under vibration condition.7) If the groundwater table in soil slope is lower than half height of the slope, the increasing of groundwater table will not effect on the stability and deformations of soil slope obviously. If the groundwater table is higher than the half height, the dynamic strength and the deformations of soil slope descends markedly with the groundwater table ascending.8) The seepage on backwall of No.6landslide of Tohoku line is the decisive factor for causing the landslide during Fukushima earthquake. Because the water table on the back wall is more than2/3height of the slope, the dynamic stability declines rapidly and huge landslide happens.