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## Analysis of Rainfall Infiltration Process and Stability of Soil Slope with Multilayer Structure

HU Qing-guo 1 YUAN Ning 1 LIU Deng-sheng 1 HE Zhong-ming 1

(1.School of Civil Engineering and Architecture, Changsha University of Science & Technology , Changsha, Hunan, China 410114)

【Abstract】In order to analyze the infiltration process and stability variation of soil slope with multilayer structure under different rainfall conditions, a method for calculating the rainfall infiltration depth and stability of multilayer soil slope were proposed based on rainfall infiltration mechanism and theoretical calculation formula of rainfall infiltration depth of homogeneous soil. The proposed method and numerical analysis method were used to calculate the depth and stability of rainfall infiltration and stability of soil slope with multilayer structure. The results show that the formula for calculating the infiltration depth of multilayer slope under the influence of rainfall intensity and rainfall time duration is established. The results obtained from the formula are basically consistent agree with the numerical analysis results. That is to say, the formula can better reflect the rainfall infiltration process of the multilayer soil slope. In the process of rainfall infiltration, the volumetric water content and pore water pressure near the slope surface dramatically increase and change greatly at the interface of soil layer. Meanwhile, the slope surface reaches saturation firstly, and the volume water content of second layer soil reaches saturation subsequently. The safety factor of slope decreases with the increase in rainfall infiltration depth in the process of the rainfall infiltration. The safety factor changes suddenly when the wetting front reaches the soil interface. On account of the difference of permeability coefficients between different soil layers, it is easy to form seepage flow parallel to the slope surface at the interface of the soil layer, thus causing a wide range of fluctuation of the slope safety factor. The slope is prone to be failure this moment.

【Keywords】 road engineering ; rainfall infiltration ; numerical analysis ; soil slop ; stability ;

【DOI】

【Funds】 National Natural Science Foundation of China (51678073, 51508040) Hunan Provincial Key Research and Development Program (2016SK2023)

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This Article

ISSN:1001-7372

CN: 61-1313/U

Vol 31, No. 02, Pages 67-74

February 2018

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