Process Of Rainstorm-triggerred Shallow Loess Landslides

Loess landslide induced by continuous heavy rainfall is one of the most important engineering geological problems in Northwest Loess Plateau of China.In Northwest China,the annual rainfall is concentrated and the rainfall is large.Under the continuous strong rainfall,the water rapidly infiltrates into the loess slope,which makes the soil strength of the slope drop suddenly and induces the loess landslide.It is of great significance to study the forming process of this kind of landslide for disaster prevention and mitigation in northwest China.In this paper,the physical properties of slope soil during rainfall and rainfall were studied by field and laboratory tests,and the seepage process of slope under heavy rainfall was simulated by software.Finally,the variation process of slope stability and its limiting factors during rainfall are analyzed.The main contents of the study are as follows:(1)Through the field test to simulate the continuous heavy rainfall infiltration loess slope process,monitor the change of the water content and substrate suction force of slope soil during the rainfall,and finally the sampling work is carried out with the field test.(2)Through the indoor physical tests to obtain the specific gravity,density,moisture content and particle size distribution of the soil etc,and through the water test to study the permeability coefficient and SWCC curve of the original specimen,then analyze indexes of the samples with different depths.Finally inverse the hydraulic parameters are in combination with the field monitoring data.(3)Through the direct shear test of 8 water and 7 vertical pressure on the undisturbed sample,study characteristics of shear strength index of shallow loess under different water content,and softening characteristics and the envelope of the nonlinear failure intensity.Finally the shear strength parameters are predicted based on SWCC curve.(4)The seepage process of slope internal moisture during rainfall is studied by SEEP/W module in Geo-Studio software,and the slope height and slope degree which affect the seepage process are quantitatively analyzed by changing the model.(5)Combined with the calculation results of SEEP/W module in Geo-Studio software,the variation of slope stability during rainfall was studied by SLPOE/W module,and thefactors restricting slope stability in actual process were analyzed in combination with field tests.