Numerical Simulation And Analysis Of The Settlement Variation Law Of Widening Subgrade Of Mountainous Highway

With the rapid development of economy,road reconstruction and expansion project is an effective method to cope with the rapid increase of traffic volume.However,the uneven settlement of the old and new roadbed is a common problem in the road reconstruction and expansion project,and the difference settlement will cause various roadbed road diseases.The difference settlement between old and new roadbed is a problem that must be considered in the road reconstruction and expansion project.To solve the problem of different settlement between old and new roadbed,theoretical analysis,numerical simulation and geotechnical centrifuge test are used to analyze and study.The main conclusions are as follows:(1)Based on the model,the paper analyzes the change law of the non-uniform settlement of the roadbed.Analyses the general roadbed,roadbed side shoulder wall and three kinds of widening subgrade retaining wall embankment slope section,under the condition of different roadbed widening the width and widen the height changes of subgrade differential settlement,analyzed the new roadbed strength on the influence of differential settlement.Under the three different sections,the change of the roadbed broaden the width and height of obvious effect on differential settlement of the widening subgrade,small embankment wall effect on the change of the settlement,shoulder wall add changed on the surface of the subgrade settlement deformation of the change rule and the state,to a certain extent,reduces the differential settlement of widening roadbed.The variation law of differential settlement and the influence of support structure on the difference settlement of old and new roadbed are analyzed in detail.(2)In this paper,the non-uniform settlement of roadbed is analyzed by geotechnical centrifuge test,and the influence of reinforcement and rock fill on differential settlement is discussed at different subgrade heights.The differential settlement of new and old roadbed along with the increase of embankment height and change obviously,reinforcement treatment of subsidence is limited,but balanced within the roadbed uneven settlement,rockfill to reduce the effect of differential settlement of subgrade surface is reduced the uneven settlement of new and old roadbed.Compared with the numerical simulation,the comparison shows that the geotechnical centrifuge test is basically consistent with the numerical analysis.By means of numerical simulation,the possibility of adopting different engineering measures to reduce the difference settlement is analyzed.(3)Based on the structural analysis of pavement structure,the control standard of subgrade differential settlement is proposed based on the structural analysis of pavement structure.The influence of the change of modulus and thickness on the additional stress of the road surface is analyzed under the influence of differential settlement control index.The results show that the control of base modulus and layer thickness can effectively reduce the additional stress at the bottom of the pavement structure,and reduce the differential settlement of the subgrade surface.