Study On Slope Stability Under Rainfall And Earthquake Interaction Based On MIDAS GTS

Southwest China is located on the seismic belt,and there are many earthquake disasters.In addition,the rainfall in this area is large and the annual rainfall time is long.Therefore,it is necessary to study the slope stability under the joint action of rainfall and earthquake.In this paper,k342 + 080 ～ k342 + 280 slope located in the middle of the slope near didiyan village,caiyuhe Town,Huidong County,Liangshan Prefecture,Sichuan Province is selected as the engineering background.Midas GTS software is used in different rainfall intensity,different earthquake acceleration,and different rainfall intensity-Under the condition of combination of seismic acceleration,a three-dimensional model is established to study the stability and deformation law of the slope under different rainfall types,seismic acceleration and rainfall earthquake combination;at the same time,under the most unfavorable rainfall and earthquake coupling action,the stability of the slope after the anti slide pile is most likely to be damaged is compared with the stability without anti slide pile.The contents and achievements of this paper can be divided into the following parts:(1)Under the condition of rainfall,with the increase of rainfall intensity,when the rainfall intensity reaches 80 mm / D,the increase of pore water pressure will increase significantly.With the increase of rainfall intensity,the pore water pressure changes from negative pressure to positive pressure.With the increase of rainfall intensity,the maximum displacement value of slope increases.When rainfall intensity is greater than 80 mm / D,the maximum displacement value increases significantly.With the decrease of rainfall duration,the maximum displacement surface area decreases.When the rainfall duration is more than 4 days,the maximum displacement surface area is mainly concentrated at the top of the slope.When the rainfall duration is less than 4days,the maximum slip surface area decreases significantly and is located at the foot of the slope.From all directions,the sensitivity of x-axis displacement is greater than z-axis,Y-axis displacement does not occur.With the increase of rainfall intensity,the safety factor of slope decreases.When the rainfall intensity is greater than 80 mm / D,the safety factor decreases significantly,and the stability of slope decreases significantly.(2)Under the seismic condition,with the increase of the seismic acceleration,the maximum principal stress of the slope increases obviously in a zigzag shape(0.15 g at the inflection point),which is positively related to the seismic acceleration,and the maximum stress of the slope appears at the slope toe.According to the displacement nephogram,the maximum displacement occurs at the foot of the slope.The total displacement values under five different working conditions are 14.2mm,16.9mm,21.6mm,29.9mm and 57.9mm,respectively.With the increase of seismic acceleration,the corresponding displacement values also increase,and the increase of displacement is more and more large when the seismic acceleration reaches 0.15 g.From the analysis of displacement sensitivity in all directions,Z axis is the largest,X axis is the second,Y axis is the smallest and far less than X axis.With the increase of horizontal acceleration,the safety factor decreases in a zigzag form(0.15 g at the inflection point),and the stability of the slope is also weakened.(3)Under the condition of rainfall earthquake combination,the stress of slope has a positive correlation with the seismic acceleration,on the contrary,it has a negative correlation with the rainfall intensity.When the rainfall intensity is 40 mm / D,the duration is 2D and the seismic acceleration is 0.2g,the maximum principal stress of slope model is 849 kpa.When the rainfall intensity is 160 mm / D,the duration is 2D,and the seismic acceleration is 0.2g,the maximum displacement is 158.3mm.The foot position of x-axis displacement and y-axis displacement is most sensitive to rainfall earthquake interaction,while z-axis displacement is more sensitive to foot and top of slope.The sensitivity of x-axis is greater than that of z-axis.The sensitivity of y-axis is very small,which can be summarized as small.Under the joint action of rainfall and earthquake,the rainfall intensity is 40 mm / D,and the maximum safety factor is when the seismic acceleration is 0.05g;the rainfall intensity is 160 mm / D,and the minimum is when the seismic acceleration is 0.2g.(4)According to the slope stability under the joint action of rainfall and earthquake,it is indicated that Based on the importance of MIDAS GTS software,a three-dimensional model is established after adding anti slide piles under the most unfavorable working condition under the combined action of rainfall and earthquake.After adding anti slide piles,the anti slide performance of the slope itself is significantly enhanced,and the displacement is also significantly reduced.The safety factor is increased from 0.46 without anti slide piles to 1.39 meeting the requirements of more than 1.15 in technical code for slope engineering of buildings(gb50330-2013)The integrity was significantly improved.