Study On Mechanical Properties Of Geogrid Reinforced Soil Slope Under The Coupling Of Earthquake And Rainfall

Slope is one of the important structures in structures.China's mountainous area accounts for 2/3 of the country's land area.With the construction of mountainous areas more and more,landslides caused by natural disasters such as earthquakes and rainfall have caused huge economic losses and casualties for the construction and operation of water conservancy,hydropower,transportation and other projects.Under this background,the geogrid reinforced soil slope is characterized by its simple construction,good earthquake resistance,strong adaptability to the foundation,beautiful appearance,environmental protection and good economic effects.It has good application prospects in the fields of highway,railway and water conservancy.However,its working performance is more complicated,especially the mechanical properties under the coupling of earthquake and rainfall is not clear.Therefore,in order to promote this technology in engineering,it is necessary to study the coupling of earthquake and rainfall.On the basis of previous studies,this paper takes reinforced soil slope in a highway connecting section in Yunnan as the research object,determines reasonable material parameters through field penetration test and indoor geotechnical test,establishes numerical calculation model,and based on the finite difference principle,the influence of different geogrid stiffness,reinforcement ratio and layout on lateral displacement of reinforced soil slope under earthquake action is analyzed.The variation of stress and strain of reinforced soil slope under uncoupling and coupling states of seepage fields and stress fields under rainfall is studied.The changes of stress field,displacement field and shear strain increment under the coupling of earthquake and rainfall are analyzed comprehensively.Through the analysis,some useful conclusions are drawn,which is of great significance for perfecting the theoretical system of geogrid reinforced soil slope and guiding the construction of practical projects.The work done in this paper and the conclusions reached are as follows:(1)The current status of theoretical research at home and abroad under the earthquake and rainfall of reinforced soil slopes is summarized.(2)For the actual project of a highway connecting section in Yunnan,the construction site investigation,geotechnical test,etc.,collated relevant information,and obtained the geological hydrology situation along the project.The finite difference theory is used to numerical simulate the flexible reinforced soil slope under the coupling of earthquake and rainfall.(3)In order to explore the effects of static stress field and seepage field on the stress field and displacement field of natural slope and reinforced soil slope,a numerical model of natural slope and reinforced soil slope is established according to engineering practice.Considering the coupling and uncoupling conditions,the stress and deformation laws of the reinforced soil slope are summarized.The results show that the calculation results when considering the coupling effect are more unfavorable and closer to the engineering practice.(4)In order to analyze the influence of different tensile stiffness,reinforcement ratio and arrangement form on the lateral deformation of reinforced soil slope under earthquake action,based on the initial model of reinforced soil slope,the seismic load is inputted and the dynamic calculation model is established.Considering the influence degree of each calculation parameter on the working performance of geogrid reinforced soil slope,and comparing them,the conclusions that are meaningful to the actual project.The results show that the greater the stiffness of the geogrid,the smaller the lateral displacement of the slope;the reinforcement ratio has a relatively weak influence on the lateral deformation of the reinforced soil slope;the reverse reinforced soil slope has good integrity.(5)In order to explore the influence of rainfall and earthquake on the stability of reinforced soil slope,according to the stress and seepage computer theory of finite difference software,the coupling of earthquake after rainfall,the coupling of rainfall after earthquake and the coupling of earthquake and rainfall are considered.The results show that the influence of the coupling of earthquake after rainfall on the reinforced soil slope is greater than the impact of the coupling of rainfall after earthquake on the reinforced soil slope,but it is less than the coupling of the earthquake and rainfall.