Settlement Calculation Of Bidirectional Reinforced Composite Foundation With Consideration Of Soil Arching

With the rapid development of highway,railway and other infrastructure construction in China,soft inevitably encountered in the process of highway(railway)road construction.The bidirectional reinforced composite foundation composed of "horizontal reinforced body + vertical reinforced body" is widely used because it combines of the two kinds of reinforced body composite foundation.At present,the theoretical research of still in the preliminary stage,and there is no unified method for the deformation calculation.However,deformation control is one of the important indexes for the design of bidirectional reinforced composite foundation.Therefore,based deformation bidirectional reinforced this paper carried out an in-depth study on its settlement calculation and engineering application.The main research contents and results are as follows:Firstly,this paper briefly introduces the load-bearing mechanism of rigid pile,flexible pile and gravel column.And analyze the reinforcing mechanism of reinforced cushion layer and embankment soil arching effect.On this basis,the relationship between the soil arch effect and deformation of piles and soil is been proposed as the main research object of the study through the study of the mechanism for the system of embankment-reinforced cushion layer-pile soil reinforcement area.Second,for the characteristic of the bidirectional reinforced,assuming that composite foundation of pile and soil with different stiffness of the spring system.The geotextile reinforced cushion layer for positioned Timoshenko beam on elastic foundation,exploratory the symplectic geometric algorithm is applied to consider the soil arch effect of double composite settlement calculation.By establishing expression in displacement balance differential equation,based on the variational principle of elastic mechanics,the potential energy of the Timoshenko beam was derived and its corresponding Lagrangian function.A settlement calculation formula for bidirectional reinforced composite foundation is been built based on the Hamiltonian system.The calculated parameters such as the calculated width,the flexural stiffness of the stiffened cushion,the spring stiffness co efficient and the shear stiffness of the stiffened cushion are discussed.Then,based on the theory of natural equilibrium arch,a new settlement calculation method for bidirectional reinforced composite foundation is been proposed considering the effect of soil arch and the flexural and tensile properties of reinforced cushion layer.This method can comprehensively reflect the influence of soil arch height,pile net distance,flexural stiffness of reinforced cushion,pile-soil stress ratio and pile-soil stiffness ratio on the bidirectional reinforced composite foundation under embankment load.Finally,the design method of bidirectional reinforced composite foundation is applied to a practical project,the results calculated by the proposed method and the stratified summation method are compared with the settlement values measured by field tests.The analysis results show that it is feasible to apply the new method for settlement calculation of composite foundation with bidirectional reinforcement considering soil arch effect in engineering.