Model Test And Numerical Simulation Study On Stress And Deformation Characteristics Of Pile-supported Reinforced Embankment

Pile-supported reinforced embankments can control post construction settlement and constrain lateral deformation of embankments,meet the overall stability and deformation control requirements of soft soil embankments,and have good engineering characteristics.They have been widely used in many engineering constructions both domestically and internationally.This thesis is based on indoor model tests and ABAQUS finite element numerical simulation analysis of the stress and deformation behavior of pile-supported reinforced embankments.By studying and analyzing the changes in the pile-soil stress ratio at the bottom of the embankment,the geotextile strain in the cushion layer,and the vertical displacement settlement of the soft foundation surface under various influencing factors,the stress and deformation characteristics of pile-supported reinforced embankments are revealed,In particular,a systematic study was conducted on the effectiveness of the arrangement of reinforcement materials,in order to provide experience and theoretical support for the design and construction of pile-supported reinforced embankments in the future.The main research content and achievements are as follows:(1)Extensive literature review on pile-supported reinforced embankments has been conducted,summarizing the current research status of pile-supported reinforced embankments.In response to the shortcomings in existing research,the research technical route of this article has been proposed.Summarized the basic theory of foundation treatment,introduced the basic structural composition,failure mode,and bearing mechanism of pile-supported reinforced embankment,and explained the working mechanism of the cushion layer,the role of pile soil reinforcement area,and the calculation of pile-soil stress ratio.(2)Conduct indoor model tests on the stress and deformation behavior of pile-supported reinforced embankments,and analyze the changes in pile-soil stress ratio,geotextile strain,and surface settlement of soft soil foundation under the influence of factors such as the presence or absence of reinforcement treatment in the cushion layer,reinforcement material laying process(reverse wrapping or not),reinforcement material strength,reinforcement material arrangement layers,and pile spacing.The study found that: when the cushion layer is reinforced,The tensile film effect of geotextile has strengthened the effect of soil arching effect.The strain values at each measuring point of geotextile are related as follows: pile cap edge>pile cap center>two pile centers>four pile centers.When the geotextile is backfilled,the cushion filling material is used to anchor it,which can effectively increase the pile-soil stress ratio and reduce the deformation and settlement of the soft foundation surface.The use of high-strength geotextile has a significant effect on improving the pile-soil stress ratio and controlling the displacement and settlement of soft soil foundation.The more layers of reinforcement,the stronger the ability of the tensile membrane effect to transfer load,and the greater the stress ratio between pile and soil;When multi-layer geotextile is used for reinforcement treatment in the cushion layer,the strain generated by the lowest layer geotextile is the highest,and the internal tension is the highest.The setting of pile spacing has the greatest impact on the deformation and settlement of soft soil foundation.(3)Using ABAQUS finite element analysis software,numerical simulation was conducted on the stress and deformation behavior of pile-supported reinforced embankments.The variation patterns of pile-soil stress ratio,geotextile strain,and soft soil foundation surface settlement under the influence of factors such as reinforcement position,reinforcement spacing,cushion modulus,and pile cap size in the cushion layer were analyzed.The study found that the closer the reinforcement material placement in the cushion layer is to the upper fill load,the greater the pile-soil stress ratio,The smaller the strain value of the reinforcement material,the smaller the settlement on the surface of the soft foundation.Adopting a two-layer reinforcement arrangement,when the reinforcement spacing is close,the reinforcement effect of the reinforcement material is enhanced,the pile-soil stress ratio increases,the strain of the reinforcement material decreases,and the settlement of the soft foundation decreases.The larger the elastic modulus of the cushion layer,the greater the overall stiffness,and the greater the pile-soil stress ratio;The larger the modulus of the cushion layer,in turn,it constrains the deformation of the reinforcement material,and the smaller the strain value of the reinforcement material.The longer the side length of the pile cap,the greater the stress ratio between the pile and soil,the less the load on the soil between the piles,the lower the level of tensile membrane effect exerted by the reinforcement,and the smaller the strain.