Research On Deformation Characteristics Of Prestressed Reinforced Soil Embankment Structure

The strain that occurs in the initial stage of deformation of traditional reinforced soil structures is not sufficient to mobilize the tensile load of the reinforced material,and due to the shaking and settlement of repeated loads such as traffic loads and seismic loads,there will be phenomena such as creep,sliding,and peeling of the reinforcement,which cannot effectively release the deformed stress of the reinforcement,greatly affecting the reinforcement effect of the reinforcement.Therefore,prestressed reinforced soil structures with prestressed maintenance functions have been developed and improved.Prestressed reinforced soil structure is a new and unique structure formed by vertically penetrating prestressed component materials into reinforced fill inclusions on the basis of traditional turn-back reinforced soil structures.This structure can reduce the plastic deformation of the soil,which is beneficial for reducing settlement after construction.At the same time,pre-stressing causes the reinforcement to deform in advance,exerting the tensile force of the reinforcement in advance,increasing the constraint pressure around the soil,limiting the lateral deformation of the soil,enhancing the anti deformation ability of the soil,and improving the stiffness of the structure.The research on the deformation characteristics of prestressed reinforced soil structure is of great significance for improving the theoretical design of prestressed reinforced soil,accurately predicting the deformation of prestressed reinforced soil structure,guiding engineering practice,control engineering cost and preventing engineering disasters.In order to explore the structural deformation characteristics of pre-stressed reinforced soil embankment,a constitutive model of prestressed reinforced soil structure is established.This thesis conducts a series of theoretical and laboratory model tests around the deformation characteristics of reinforced soil structure and pre-stressed reinforced soil structure.The research content and main conclusions are as follows:(1)Based on the Duncan-Chang hyperbola model and the equivalent confining pressure theory of reinforced soil,the composite modulus of reinforced soil composite structure is derived through the relevant parameters obtained from the triaxial test of plain soil and the tensile test of reinforcement materials.(2)Through triaxial compression tests,explore the effects of factors such as the type of reinforcement material,number of reinforcement layers,and confining pressure on the reinforcement effect of reinforced soil,and verify the reliability of the inferred constitutive relationship of reinforced soil based on the results of triaxial tests.The results show that under the same number of reinforced layers,as the confining pressure increases,the bearing capacity of reinforced soil increases,and the efficiency of improving bearing capacity decreases;Under the same confining pressure,as the number of reinforced layers increases,the bearing capacity of reinforced soil increases,and the efficiency of improving bearing capacity is higher;The calculated stress-strain curves of reinforced soil under different conditions have good consistency with the experimental values,proving that the derived constitutive relationship of reinforced soil is effective and can accurately calculate structural deformation.(3)Because the prestressed reinforced soil structure itself has the surrounding pressure caused by prestressing,the mechanical characteristics of the prestressed reinforced soil structure under vertical load tests are similar to those of the reinforced soil sample in triaxial tests.Therefore,based on the derived composite modulus of reinforced soil,the composite modulus of prestressed reinforced soil structure can be further derived,and a numerical calculation method for the deformation characteristics of prestressed reinforced soil structure based on the Duncan-Chang model in vertical load model tests can be proposed.(4)Taking the engineering example as the mock object,the scale model test of prestressed reinforced soil embankment structure is designed,and the reinforcement effect and the capacity of prestress on improving the bearing capacity of embankment and controlling differential settlement are explored.The research results indicate that prestressed reinforced soil structure can significantly improve the bearing capacity of the roadbed and reduce differential settlement;The greater the prestressing force,the greater the bearing capacity of the structure,and the stronger the ability to control differential settlement;The experimental results and numerical calculations of the prestressed reinforced soil embankment model have good consistency,proving that the constitutive relationship of the prestressed reinforced soil structure is effective and can be used to accurately calculate the deformation of the prestressed reinforced soil structure.