| In this paper,the loess fractured slope in the southern Loess plateau of Jingyang is taken as the research object.Through field survey,laboratory test,model test,numerical simulation and other methods,the propagation law of loess fractured slope and slope stability under the collaborative action of rainfall and overburden are studied.The response characteristics of stress field,displacement field and seepage field of loess slope and the expansion law and influence range of structural surface were clarified,and the deformation and failure mode of loess slope under rainfall and stacking was proposed,and the main results were as follows:(1)The stress concentration and variation law of slope were determined: in the process of loading and rainfall,the z-direction stress in the slope has the largest variation amplitude,and the two groups of slopes under different working conditions have stress concentration and negative stress zone,but the regional location and magnitude of various stresses under different conditions are different.Rainwater enters the slope through the preset cracks,and has a significant impact on the stress distribution in the area near the preset cracks.(2)The settlement characteristics of loess slope were elucidated: in the process of loading and rainfall,the displacement response trend of the two groups of slopes is basically the same.The deformation area of the slope is mainly distributed under the pressure plate and near the slope surface.The overall displacement change is mainly vertical settlement displacement,and the rainwater infiltration is the main cause of the large settlement of the slope.(3)The water migration and permeation law of the loess slope on the structural surface was studied: During rainfall,the response states of preset structures with different inclination angles to rainfall infiltration are obviously different.The greater the inclination Angle of structural plane,the greater the rainwater infiltration,the more obvious the crack propagation phenomenon,the more likely the dominant seepage channel appears in the structural plane area,and the soil in this area always reaches saturation state before other areas.The overall trend of infiltration response speed was as follows: preset structural plane region > slope foot region >preset structural plane end region > slope side region.(4)The expansion law of slope structural surface was revealed: in the process of loading and rainfall,the near-slope crack propagation law of the two groups of slopes is basically the same,and the crack propagation law of the preset structural plane with different inclination angles is quite different.In the loading stage,with the increase of load,the crack propagation and extension phenomenon will appear on the near slope,and the crack propagation at the preset structural plane is not obvious.When entering the rainfall stage,the larger the inclined Angle of the preset structural plane,the easier the rainwater infiltration,the crack expansion and reclosure of the slope.Under the action of soil and water coupling,the slope surface collapses and destroys the slope structure.(5)The deformation and failure mode of loess structural surface slope under rainfall and stacking was proposed:Under the rainfall and loading,the slope will be subjected to compression and shear forces,resulting in a concentration of tensile stress in the shoulder area and a concentration of shear stress in the foot area.The deformation and damage pattern of loess slopes under the rainfall and loading can be divided into soil compacting and local creep stage-infiltration weight gain and fracture expansion stage-shallow sliding damage stage-deep sliding damage stage. |
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