Instability Mechanism Of Gently Inclined Soil Slope And Study On Treatment Method Of Blind Gravelly Ditch

In the past 40 years,the extreme weather of heavy rainfall has become more and more serious in Southwest China,and the landslide accidents caused by it have increased slightly.A new type of landslide induced by heavy rainfall,namely gently inclined soil landslide,has appeared.According to the traditional cognition,this kind of slope is not prone to landslide instability.Through the analysis of a large number of engineering examples,the author summarizes the similarities of this kind of gently inclined soil landslide and finds out its instability mechanism.In this article,through indoor test,numerical simulation and theoretical analysis method,this kind of slope soil slope instability mechanism is analyzed and the failure mode,and through the results of numerical simulation and field landslide phenomenon provides retaining wall + macadam blind ditch way of governance,and through the numerical simulation proves the feasibility of this way of governance,through three management scheme comparison and analysis,It proves the security and economy of this governance method.Through a large number of data statistics,this kind of gently inclined soil landslide with special structure is widely distributed in the southwest area,so the study has practical engineering significance.In this paper,a medium-sized gently inclined soil landslide in Jiangyou of Mianyang City was selected as the research object,and the following research results were mainly obtained:(1)According to the laboratory direct shear test,the shear strength of the contact surface between the sliding-zone soil-strongly weathered mudstone after two days of immersion is far less than that of the saturated silty clay,which provides a parameter basis for the shear strength of the contact surface between the sliding-zone soil-strongly weathered mudstone in the underground water in the numerical simulation.(2)According to the formation structure of gently inclined soil slope,a simplified permeability model was established.Through FLAC3 D numerical simulation,Slope body pore water pressure is analyzed with the change rule of rainfall intensity and rainfall,slope devices for trailing edge Z axis displacement and the trailing edge of slope body and the total displacement along with the rainfall intensity and rainfall long after the change rule,retaining wall,the horizontal force and the point with the rainfall intensity and rainfall during long change rule,through the analysis of the results of numerical simulation,The failure mechanism of this kind of gently inclined soil slope is explained.By combining the results of numerical simulation and failure like now,puts forward such slowly inclined soil landslide failure mode of two kinds of slope roof failure and floating slope sliding failure,by means of mechanics theory,and derived the failure of the two types of critical condition,to analyze this kind of gentle dip earthiness landslides have provided the certain theory reference significance.(3)analyzed the difficulties of such slowly inclined soil landslide governance,and put forward the blind ditch of debris + retaining wall way of governance,through the numerical simulation proves the feasibility of this control method,and through the comparison of gravel blind ditch + gravity retaining wall and anti-sliding pile retaining wall,apron anti-sliding retaining wall three governance economic the practicability of the project,Finally,it is determined that the treatment scheme of blind gravel ditch + retaining wall is a safe,reliable and economic treatment method for this kind of gently inclined soil landslide,and provides a certain reference treatment method for this kind of landslide.