The Sheet Pile Wall In Loess Area Embedded Section Stress Mechanism And Dynamic Response Analysis

At present,in the railway engineering design,sheet pile wall is widely used in the slope protection of high embankment and deep cutting,which horizontal bearing capacity depends largely on the bearing capacity of the foundation and the buried depth of the embedded section.If the thickness of the soft foundation is large and the anchorage resistance of the construction anchor can not be effectively guaranteed,in order to control the lateral deformation of the pile,it is necessary to reinforce the foundation before the pile.This paper relies on the construction of Sanmenxia railway,a part of the Menghua Railway construction project,where the sheet pile wall retaining slope in loess area.In order to control the lateral deformation of the pile,we chose the jet grouting pile to reinforce the foundation in front of pile.Through the discussion of sheet pile wall stress mechanism and combined with theoretical analysis,numerical simulation and model test,to studying the rule of coefficient value of foundation before the pile in loess area;comparing the strengthening effect of different design parameters of the jet grouting pile;analyzing the dynamic response of pile wall,subgrade reaction and slope stability under the earthquake after reinforcement.The main work and conclusion of this paper are as follows:(1)Through reading the relevant documents to comprehending the stress mechanism of pile.According to elastic foundation beam theory,deduces the basic differential equation of pile wall based on M method and get the numerical solution.(2)Combined with the actual project,analyzing the reinforcement effect in different design parameters of pile foundation and subgrade reaction before and after the reinforcement by using Flac3 D.The study found: in the depth of pile wall fixed length 1/3 to 1/2 within the scope,the economic effect of the strengthening is the best.After reinforcement,a part of earth pressure in front of pile transfers to 1m range of ground depth,but it has no effect on earth pressure behind the pile.The deeper the strengthening depth is,the greater the earth pressure transfer rate is.In the reinforcement range of the rotary jet pile,the coefficient of foundation and the m value before the pile are increased in varying degrees.The main growth region isconcentrated between the surface and depth of 1/3 embedded section.(3)The model test is carried out on the basis of numerical simulation,mainly for the analysis of the length of the rotary jet pile,and the results of the test are basically consistent with the numerical simulation results.(4)Analysis of one way seismic dynamic based on static analysis,which can be found that strengthening the foundation in front of the pile can effectively fix the sheet pile wall,control the displacement of the pile body under the dynamic action,and reduce the stress of the pile body.Secondly,the foundation reinforcement in front of pile can effectively control the increase of earth pressure in front of pile during earthquake.