Study On The Seepage,stability And Deformation Of The Expansive Soil With Cracks Under Rain

With the development of our country's economy,more and more high-grade highways are required which company with more slope.What's more,the expansive soil has a wide distribution in our country,the landslide due to rainfall is a common engineering problem.The character of “swelling due to wetting and shrinkage due to drying” make the slope generate crack during the change of atmospheric,and the crack will influence the seep,stability of the slope during rainfall,at the same time,the deformation of the expansive soil has influence on the engineering.So it's necessary to study the influence of the crack's existence,the crack's depth and the crack's location to the seep,stability and deformation of the slope during rainfall.Combined with the engineering data,This paper use the numerical analysis software to study the influence of the crack's existence,the crack's depth and the crack's location to the seep,stability and deformation of the slope under rainfall.The main research contents are as follows:1.By the analysis of the existing theories and the experiments,presenting a method to describe the development process of the crack under rainfall.2.Analyzing the water content distribution of the slope inner with cracks and without cracks.Results show that the cracks will influence the seepage of the slope.Analyzing the influence of crack's depth to the seepage of the slope.Results show that the depth of crack has an influence on the seepage field and the change velovity of the water content.The seepage field increase with the increase of the depth;and in earlier rainfall course,the change velovity of the water content decrease with the increase of the crack depth,while at the end of the rainfall,the change velocity of the water content increase with the increase of the crack depth.Analyzing the influence of crack's location to the seepage field of the slope.Results show that the difference of the water content is greatest when the crack located on the top of the slope,while the difference of the water content is minima when the crack located under of the slope.3.The exist of the crack has a big influence on the stability of the slope.Analyzing the influence of crack's depth to the stability of the slope,results show that the stability decrease with the increase of the depth,and the speed of the decrease of the stability is slow down,what's more,the depth of the crack will influence the location of the potential glide plane.Analyzing the influence of crack's location to the stability of the slope,results show that the stability when the crack located at upper and under of the slope is lower than the crack located on the top of the slope,what's more,the location of the crack has a little influence on the location of the glide slide.4.Through the constitutive model,make it possible to use the change of suction to predicate the deformation of the expansive when rainfall.By analyzing the influence of rainfall range to the deformation of the slope,showing that the rainfall range has a big influence on the deformation of the top.At the same time,analyzing the influence of crack to the deformation,results show that crack has a big influence on the deformation of the slope,and the deformation are mainly in the cracking layer;The deformation of the slope increase with the increase of the crack depth,and all have a mutation around the bottom of the cracking layer.