Effective Stress Form For Slope Stability Analysis Respectively Based On Janbu Method And Sarma Method

To consider the effect of seepage on slope stability,a new evaluation approach in the effective stress form of Janbu/Sarma method was proposed,which differs from the original Janbu/Sarma method expressing in total stress form.The new method can calculate the effect of seepage force on the slope stability in terms of positions of phreatic surface.The previous method in total stress form takes water-soil mixture as the research object,and the pore water pressure around the soil is considered.The novel approach in effective stress form focuses on soil skeleton,and takes the seepage force into account instead of pore water pressure.The saturating weight and floating weight of soil should correspond to the calculation of pore water pressure and seepage force respectively.To verify effective stress form of Janbu method,various types of slopes were iteratively solved to calculate the safety factors,and the results were compared and analyzed with the original one.The results show that the two methods obtain al-most same value of the slope stability safety factor,and some certain regularity differences in the value of the internal forces and inter-slice forces of the soil slice.In the soil slope without groundwater,the results computed from the two approaches are entirely the same.And then to verify effective stress form of Sarma method,various types of slopes were iteratively solved to calculate the critical acceleration factor,and the results were compared and analyzed with the original one.The results show that the two methods obtain almost same value of the critical acceleration factor,and even more safely in the presence of groundwater.In the slope without groundwater,the results computed from the two approaches are entirely the same.The approach in the effective stress form of Janbu/Sarma method considers the effect of seepage to the slope stability,which can be a feasible method in slope stability analysis.