Stability Analysis And Calculation Of Embankment Supported On Composite Foundation Reinforced With Rigid Piles

With the development of economy and society,highway has been playing an increasingly important role.In the rapid construction process,especially in soft soil areas,there have been many engineering problems.As a kind of soft soil subgrade treatment,composite foundation reinforced with rigid piles has been widely used in recent years.Through this method,the problems of large post-construction settlement and insufficiency of the ground bearing capacity have been solved effectively.However,the stability of embankment has not been paid enough attention in practical engineering.The stability failure of embankment occurs frequently,despite the adoption of composite foundation reinforced with rigid piles.Aiming at the stability of embankment supported on composite foundation reinforced with rigid piles,the main research works are as follows:1.In order to identify the mechanical characteristics of rigid piles and the influence of different reinforcement position,elastic modulus of pile,deformation modulus of soil on the distribution of pile's internal force,the finite element software ABAQUS is used to study the stability of soft soil subgrade reinforced with single row of rigid piles.And the direction of research is established for the following numerical analysis under the pile group conditions and stability calculation method.2.According to the equivalent shear strength method proposed by Zheng Gang,the actual distribution of the passive load and the supporting function of soil behind piles are not taken into account.Considering soil arching effect,a stability calculation method for embankment supported on composite foundation reinforced with rigid piles is suggested based on the calculation of pile's internal force by nonlinear subgrade reaction method and then verify its applicability and reliability.3.By using the finite element software ABAQUS,the cut-off mechanism of piles is introduced to analyse the instability and failure mode of soft soil subgrade reinforced with rigid piles under the pile group conditions.Based on this,the critical ratio n is proposed as the critical value for judging piles preferentially occur shearing failure or bending failure also as termination criterion for the cut-off mechanism.4.Point at the wedge sliding surface of embankment supported on composite foundation reinforced with rigid piles,the sliding mass can be divided into three parts:an active wedge,an intermediate wedge and a passive wedge.Due to the possible bending failure of rigid piles,the stability is controlled by the bending strength of the pile.The approximate solution of stability safety factor of embankment can be calculated and then verify its reliability.