Analytical Solution Of Seepage Field And Minimum Potential Energy Stability Analysis Of Unsaturated Soil Slopes Under Conditions Of Rainfall

The water and soil status inside the unsaturated soil slopes changes under conditions of rainfall,leading to the low stability of slopes and possibility of slope instability and landslide disaster.However,there is no method to reflect the change rules of water and soil status inside the slopes during the rainfall infiltration and quickly analyze the real-time stability of slopes.So,this paper studied the study on the real-time change of seepage filed inside unsaturated soil slopes under conditions of rainfall and the analysis of minimum potential energy stability.The major content and achievements are as follows:(1)Seepage field calculation model under conditions of rainfall was constructed for the unsaturated soil slopes and the seepage field control formula was derived as per law of conservation of mass,continuity of seepage and unsaturated Darcy law.Considering the initial water content distribution of the slope,the analytical solutions of real-time water content distributions in the slope when the rainfall intensity was larger and smaller than the saturated permeability coefficient were solved respectively based on the control formula and then the analytical solutions were proved through examples and tests.(2)A simpler method was applied to calculate the shear potential energy.Then,a total potential energy function of unsaturated soil slopes was built considering the potential energy changes of the slope after rainfall infiltration and based on the analytical solutions of real-time water content distribution in the slope.The changes of shear strength,dead weight and seepage force of soil mass due to rainfall infiltration was taken into account during the calculation of safety coefficient,and a new analytical method of minimum potential energy stability for unsaturated soil slopes under conditions of rainfall was proposed.(3)Sliding surfaces of any shape was created through the control of 5 parameters and genetic algorithm was utilized to realize the real-time exploration of the most dangerous sliding surface amongst the unsaturated soil slopes during rainfall in combination with the stability analysis methods proposed above.The comparison between the method proposed in the paper and limit equilibrium method verified the rationality of the creation of sliding surfaces of any shape and the exploration method for the most dangerous sliding surface in the paper.Furthermore,the impact of rainfall on the slope stability was also analyzed in the paper.(4)MATLAB was applied to develop the interface module,computing module,search module and drawing module based on above stability analysis method and the exploration method for the most dangerous sliding surface.Then,the above modules were assembled and the development of the minimum potential energy stability analysis program of unsaturated soil slopes under conditions of rainfall was completed.With this program,it was available to quickly analyze the real-time stability of slopes under conditions of rainfall.