Stability Analysis And Supporting Structure Study Of High-Steep Subgrade

With the development of national economic construction, the construction of railway and highway is developing quickly and its coverage extends to hills and mountains which brings out subgrade slope stability problems. The stability of subgrade concerns the smoothness and use safety of the engineering.To meet the alignment demand of high speed (fast) railway,a lot of supporting structures will be needed in undulating hills and mountains.The retaining wall on supported beams of pile foundation is a new type of supporting structure mainly used in subgrades where riverbanks are severely eroded, where there are steep slopes and rock heaps,where there is cover soil on the steep slopes with poor stability,where the bedrock is deeply seated and in sections which are adjacent to existing lines. Nowadays, this structure is widely used although its design theory can not keep up with its engineering application. With the development of the west regions,with the construction of more infrastructures e.g. railways,highways and water conservancies, this kind of retaining wall will be more popular. So this paper does a research on this retaining wall based at a practical site.Firstly, the stabilities of subgrade slope with or without the retaining wall on supported beams of pile foundation are both analyzed by use of SLOPE/W module in the geotechnical business software GEO-SLOPE which is used to analyze the slope stability on the basis of one high-steep subgrade site. Two schemes of a filling subgrade without any protection and the one with retaining wall on supported beams of pile foundation are compared.Secondly, the retaining wall on supported beams of pile foundation at a practical site is analyzed to work out the distribution of internal forces in the wall according to the analysis of the existing computating theories of internal forces in such retaining walls.Then, numerical analysis of supported beam and parts of pile foundation in the wall is carried out adopting the finite element business software-ABAQUS. It analyzes the influence of the retaining wall stiffness on supported beam and calculates how the eight major aspects including the loads on the top of the pile (vertical pressure,horizontal thrust,bending moments ),deformation modulus of soft layer,deformation modulus of inlaid rocks,elastic modulus of the pile,the depth of soft layer and inlaid depth affect the internal forces and displacements of the pile foundation.Finally ,the finite element analysis of the retaining wall on supported beams of pile foundation on the establishment of a three-dimensional numerical module is performed to study the displacement changing trend of the retaining wall,stress distribution and the value and distribution of soil pressure on the back of the wall. The mechanics function machanism of the retaining wall on supported beams of pile foundation is obtained. It also studies the field test of a retaining wall on supported beams of pile foundation at one site to verify the design and construction effects, which can provide some referrence for similar design and construction.