Numerical Simulation And Limit State Design Of Inclined Cantilever Sheet-pile Retaining Wall

With the vigorous promotion of traffic infrastructure construction in the western region of China,the development of supporting and retaining structures for steep slope road founda-tions in mountainous areas is rapid.Based on the actual engineering background and accord-ing to the topography and geological conditions of the site,this paper proposes a new tilted overhanging pile and slab wall structure with simple construction and environmental protec-tion.The paper summarises the current development status of traditional and new support structures at home and abroad,and takes the tilting overhanging pile and slab wall structure as the main research object,and discusses the action mechanism of the tilting overhanging pile and slab wall.Using a combination of theoretical calculations and numerical simulations,the force and deformation characteristics of the structure under loading conditions and the influence of different layout conditions on the force and deformation of the structure are dis-cussed.Finally,the limit state design of the structure is carried out based on the reliability theory.The following conclusions are drawn from the study of inclined overhanging pile and slab walls.(1)The inclined overhanging pile and slab wall consists of an inclined pile foundation and retaining slab,which is a new type of support and retaining structure suitable for high and steep riverine mountains.The analysis reveals that the calculation method of this struc-ture can follow the traditional theory and then be modified.This paper presents a mathemati-cal derivation and calculation of the deformation mechanism and the scope of application of the structure,which provides a basis for subsequent comparison with finite element calcula-tions.The loads on the structure are reasonably distributed through the soil arch effect,and the full-blown thrust is converted into a concentrated thrust on the two adjacent piles,which effectively brings into play the role of the piles.(2)According to the relevant design parameters of the structure,a three-dimensional fi-nite element model of the structure was established,and the force and deformation law of the structure was calculated and analysed,and the results were compared with the theoretical calculation.The analysis found that the structure is suitable for rocky slopes with good integ-rity and high strength,and the weak points are at the anchorage points of the piles and at the entrance of the surrounding rock embedment.In exploring the influence of geometric ar-rangement conditions on the structure,corresponding assessment indicators were proposed according to the structural characteristics and relevant codes,and the relevant bearing capac-ity of the structure was evaluated under different assessment indicators.It was found that the reduction of the pile length of the cantilever section and the increase of the inclination angle of the pile base will improve the force state of the structure in general.When the length of the cantilever section exceeds 7m,the tension on the pile back exceeds 2MPa,so it is neces-sary to control the cantilever length of the pile slab wall appropriately,and the ratio of the cantilever section and the anchorage section is controlled at about 1.(3)Based on the reliability theory,the limit state related design of the inclined cantile-vered pile and slab wall structure was carried out.According to the relevant codes,four limit state equations were proposed for rock lateral compression stress,structural bending re-sistance,shear resistance and pile top displacement.The Monte Carlo method and the gen-eral separation method were selected for the calculation and analysis of the structure,and the reliability indexes and sub-factors of the objective function were obtained,and it was con-firmed that the structure was not failing in bending,shear and displacement,and that the rock compression needed to be controlled,and its reliability index was 2.59,and a prelimi-nary structural limit state design expression was established as (?)This paper provides a reference for the future improvement of the applicability and formation of a systematic design method for inclined overhanging pile and slab walls.