| The stability of open slope is directly related to the safety of mining workers and the economic benefits of enterprises.It is a prerequisite for ensuring the normal production of mining enterprises.There are many reasons for the instability of the slope,and the rainfall is a common cause of landslide.Based on the study of scholars at home and abroad,this paper takes the soft rock slope of east slope of Manjiazhai as the object of study.In view of its local collapse after rainfall,the slope phenomenon occurs,combined with saturated-unsaturated seepage theory,Saturated-unsaturated shear strength theory,the relevant physical mechanics test,analysis of rainfall under the action of the open-pit mine slope failure mechanism.The seepage field of the slope under rainfall condition was calculated by using SEEP module in Geo-studio.The law of slope infiltration during rainfall was analyzed.Based on the theory of seepage flow,combined with the saturated-unsaturated shear strength theory proposed by Fredlund and Morgenstern,the stability and sliding surface of slope under rainfall conditions were calculated by using Flac3d,and the influence of rainfall on slope stability was analyzed.The main contents of this paper are as follows:(1)By reviewing the relevant literature,we can understand the current research on the stability of slope under rainfall infiltration at home and abroad.Based on Darcy's law and conservation of energy,the saturated-unsaturated seepage differential equation for soft rock slope is deduced,and the corresponding definite conditions are obtained.The saturated-unsaturated shear strength theory for soft rock slope is summarized.And this is taken as the basis of finite element numerical simulation.(2)The mechanics characteristics and permeability characteristics of the rock mass in the study area are analyzed based on the technical conditions of the opencast mining of the Manzhai slope,combined with the slope research,through the indoor and field tests of the engineering rock mass,the reasonable parameters of the macroscopic rock mass And infiltration parameters,for the subsequent numerical simulation analysis to provide reliable calculation parameters.(3)The seepage characteristics of the transient seepage field of the slope under rainfall conditions:Combined with the engineering area rainfall characteristics,and use the SEEP module of Geo-studio software to simulate the variation law of the transient saturation zone and pore water pressure distribution of slope rock under different rainfall intensity and different rainfall duration.The results show that the surface area of the slope is seriously affected by rainfall,and the influence area and influence degree are controlled by rainfall time and rainfall intensity.The transient saturation zone is an important factor to consider the slope instability under rainfall,and the rainfall is the same The larger the intensity,the larger the area of the transient saturation zone.The slope affected by the slope is the first,then the slope,and finally the slope.(4)Analysis of influence of rainfall infiltration on slope stability:Introduction of pore water pressure in seepage field into stability calculation based on saturation-unsaturated shear strength theory.The stability of slope was analyzed by Flac3D strength reduction method under rainfall condition.The stability of the slope under different rainfall conditions is evaluated,and the stability of the slope is improved.The stability of the slope under different rainfall conditions is evaluated,which provides a reliable theoretical basis for the decision maker.(5)According to the calculation results of seepage calculation and stability under the slope rainfall condition,the corresponding protection measures are put forward according to the potential hazards of the slope under rainfall conditions. |
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