Detailed Analysis Of Seepage Force And Its Influence On Slope Stability

In this paper,the accurate seepage force on each soil strip is calculated based on the seepage field given by Seep/W software,and the stability analysis of the soil slope is carried out according to the accurate seepage force.At the same time,two classical calculation examples are selected to verify the rationality of the Swedish slice method and the simplified Bishop method which consider the fine accurate force.The main achievements of this paper are as follows:1.A method for calculating the seepage force is proposed.Finite element models are established in Seep/W software to calculate the seepage field,and the soil strip is divided based on the finite element mesh.For any soil strip i,the strip consists of several grid elements.The total seepage force of each soil strip could be calculated by summarizing the seepage force on these grid elements,and the position of the acting point of seepage force in the soil strip could be obtained by summarizing the moment of seepage force of each grid element and divided the sum of moments by the seepage force.2.Based on the refined analysis of seepage force,two methods for calculating safety factor of slope under seepage(the Swedish slice method and the simplified Bishop method)are derived,and two classical calculation examples in the literature are selected to verify the method in this paper.In the calculation of the safety factor,the relative error of Swedish slice method in this paper and M-P method in the literature is between-9% and-15%,the relative error of Swedish slice method in this paper and M-P method in the slope/W software is between-7% and-16%;the relative error of simplified Bishop method in this paper and M-P method in the literature is about-0.5%,the relative error of simplified Bishop method in this paper and M-P method in the slope/W software is about-2%.Meanwhile,the position of critical slip surfaces calculated by simplified Bishop method in this paper almost coincide with the original result.3.Combined with the example,the action point of the seepage force is analyzed and it is found that the action point of the seepage force on each soil strip is close to the centroid position of the infiltration area of the soil strip.Therefore,in the absence of detailed flow information,the flow field could be simplified by assuming that the seepage force is parallel to the infiltration line and locates in the centroid of the soil strip infiltration area.