Analysis Of Seepage And Stress Coupling Stability Of Soil And Rock Slope Under Rainfall Conditions

Infrastructure construction in my country is in full swing.In order to meet the increasing traffic volume,it is essential to widen and reconstruct the original roads.There have been a large number of high-filled embankments and deep cut slopes.At the same time,rainfall has caused the slopes to lose stability.One of the important factors,especially in the southwestern region where there is a lot of rain and high slopes,slopes are more likely to be damaged by rainfall.Therefore,it is essential to consider the influence of fluid-solid coupling when analyzing slope stability.In this paper,a high-cut slope in Chongqing Chayuan is the research object,combined with the theory of unsaturated seepage,and the finite element software GTS NX is used to conduct a numerical analysis of the fluid-solid coupling of the slope under rainfall conditions,and study the effects of different factors on the twodimensional The influence of slope stability is established,and a three-dimensional slope reinforcement model is established to discuss the influence of different support forms on slope stability in the case of fluid-solid coupling.The main research content and results are as follows :(1)Based on the relationship between infiltration rate and saturated permeability,the expression of the actual rainfall infiltration volume on the slope is derived.Based on the seepage theory of unsaturated soil and the theory of porous continuum,a mathematical model of the seepage field-stress field coupling under rainfall conditions is established.The mechanism of the mutual coupling of the two fields is explained: the seepage field affects the stress field by changing the effective stress,and the stress field affects the seepage field by changing the porosity and permeability coefficient.(2)Using GTS NX software,two-dimensional slope models with different rainfall intensity,rainfall duration,groundwater level,and bedrock inclination were established respectively,and fluid-solid coupling analysis was performed on the slope.The increase in pore water pressure is the main reason for the decrease in slope stability.The longer the rainfall,the worse the slope stability,and the safety factor will partly rise after the rain stops.The greater the rainfall intensity or the higher the groundwater level,the greater the safety factor of the slope.When the bedrock dip is less than 20°,the rainfall infiltration depth is almost unchanged.When the dip angle is greater than 20°,the infiltration line will develop along the interface and the infiltration depth will increase;the larger the bedrock dip,the overall safety factor will increase,but The horizontal displacement of the top soil will increase significantly,and there is a risk of collapse.(3)The support of anti-slide piles for the slope reduces the local pore water pressure at the bottom of the slope;reduces the proportion of the tension area and the plastic strain area of the slope by 50% and 67.7%;maximizes the settlement of the slope top and the horizontal displacement of the slope Decrease by 1.17% and 8%;increase the safety factor by 13%.When the length ratio of the embedded section and the loaded section of the anti-slide pile is 1,the growth rate of the safety factor converges,and the supporting effect is the best;and under rainfall conditions,the anti-slide pile is used to reinforce the slope with the inclination of the base rock above 20° The effect is more obvious.(4)The anchor frame beam support can reduce nearly 21% of the rainfall infiltration of the slope,thereby greatly reducing the impact of rainfall infiltration on the stability;the main tensile stress area of the slope has been reduced by 13.8%;the slope top settlement,slope The maximum horizontal displacement of the surface is reduced by 2% and 33.7%,and the safety factor is increased by 28%.The supporting effect is significantly better than that of anti-slide pile support.When the anchor rod insertion angle is 40°,the maximum total displacement and maximum principal stress of the slope Are the smallest,the support effect is the best.