Research On Interaction Mechanism Of High-filled Bank Slope And Truss-framed Wharf Under Variable Amplitude Water Level

High-filled technology is an effective measure to solve the problem of forming a rear land-based stacking platform in the terminal construction in the gentle river val ey area of the Three Gorges Reservoir Area.The resulting high-filled bank slope was significantly affected by the periodicity of variable amplitude water level in the reservoir area.Under the influence of variable amplitude water level,the change of physical and mechanical parameters of bank slope soil was more complicated,which leads to the unclear bearing mechanism,stress and deformation characteristics of high-filled bank slope and Truss-frame wharf structure.For this reason,this paper firstly carried out theoretical analysis of the action mechanism of variable amplitude water level on highfilled bank slope,and analyzes the existing test data.Then it establishes a threedimensional finite element calculationed model of high-filled bank slope and truss-frame wharf with ABAQUS finite element software,and analyzed the interaction mechanis m,bearing capacity and stress deformation of high-filled bank slope and truss-frame wharf system under the influence of variable amplitude water level.The specific research contents and relevant conclusions were as follows:(1)The seepage force is generated on the bank slope during the fluctuation of the variable amplitude water level.Compared with the slow rise and fall of the water level,the sudden drop of the water level is the most unfavorable condition affecting the stabilit y of the bank slope.In view of this situation,the stress state at any point of the bank slope with and without considering the seepage force is theoretically analyzed,and the equivalent relation that can simplify the influence of the seepage force on the bank slope stability into the decrease of the cohesion of the shear strength parameter is obtained.On this basis,the simplified calculation method of the bank slope stability under the influe nce of the variable amplitude water level seepage force is established by combining the equivalent relation with the strength reduction method.The feasibility and rationality of the simplified method are verified by comparing with the traditional analysis method.(2)Through theoretical analysis of the effect of variable amplitude water level on the soil mass of high-filled bank slope,it is concluded that the variable amplitude water level changes the soil mass structure and moisture content by changing the soil mass saturation and water level cycle times,thus weakening the shear strength parameters of the soil mass.Based on the existing tests,research conclusions and the equivale nt relationship of seepage force calculation established in(1)above,the variation law of soil shear strength parameters with soil saturation and water level cycles after considering seepage force is analyzed,a simplified calculation method for weakening bank slope stability by considering soil shear strength parameters under the influence of variable amplitude water level is established,and a corresponding finite element calculation model is established.(3)On the basis of the simplified calculation method and finite element calculat io n model for weakening the stability of the bank slope by considering the shear strength parameters of soil under the influence of the variable amplitude water level established above,the numerical analysis of the mechanical deformation of the high-filled bank slope and truss-frame wharf structure is carried out.The results show that the plastic strain value of high-filled bank slope gradually increases with the increase of soil saturation and water level cycling times.After the soil is completely saturated and the water level circulates for 1000 times,the bending moment of the pile body increases by 26.02%,and the closer the pile foundation is to the rear land-based stacking platform,the smal er the safety factor of the pile foundation is.(4)According to the influence of different pile diameters on the mechanical and deformation characteristics of high-filled bank slope and truss-frame wharf structure,three models with pile diameters of 2.0m,2.2m and 2.4m are selected for numer ica l simulation and comparison.It is concluded that with the increase of pile diameter of wharf pile foundation,the stress of pile body gradually decreases,the horizontal displaceme nt of pile foundation gradually decreases,and the horizontal displacement decreases significantly.