Study On Stability Of High Fill Slope Under Rainfall Infiltration Condition

Since the reform and opening up,with the continuous investment and advance of the highway construction,the quantity of the high fill slope project increases with each passing day.Compared with the general slope,the high fill slope is more prone to instability due to the influence of external factors,and its failure mechanism is more complex.It has the characteristics of strong concealment,short occurrence time and great harm.Therefore,it is necessary to study the stability of high fill slope.Based on the expressway expansion project from Hunan Liling to Loudi,this paper selected the typical section with the largest filling height of K56+810～K56+930 for research and analysis.Through laboratory test and numerical simulation,the stability of five kinds of high fill slopes with different slope rates was studied under the condition of rainfall infiltration.This paper reveals the stability evolution law of high fill slope under different rainfall conditions.The main research work and conclusions are as follows:(1)A series of laboratory tests,such as compaction test and triaxial test,have been carried out for rock and soil mass of high fill slope.The physical and mechanical properties of soil are determined,and the results of triaxial test show that the influence of water content on the stress-strain curve is mainly reflected in the curve shape and the peak value of deviator stress.The internal friction Angle and cohesion of soil decrease with the increase of water content.(2)By using ABAQUS finite element analysis software and strength reduction method,the stability of high fill slope under five different slope rates of 20°,30°,40°,50° and 60° was simulated and analyzed.The deformation,displacement and safety factor of the above five slopes under natural conditions and maximum daily rainfall of 150 mm were studied respectively.The results show that under the two conditions,the slope safety factor decreases with the increase of slope rate,and gradually becomes gentle.(3)According to the change of rainfall type,rainfall duration and rainfall intensity,12 working conditions were set up.The high fill slope with slope rate of 30° was taken as the model,and the deformation,displacement and safety factor of slope under different working conditions were compared and analyzed.The results show that short-term heavy rainfall type,long rainfall duration and heavy rainfall have great influence on the stability of high fill slope.