Study On Influence Of Uneven Settlement Of Soft Foundation On Pavement Structure

Due to the special engineering characteristics of soft soil,the excessive settlement of soft soil foundation and the uneven subsidence of roadbed are common problems in highway engineering.This deformation will cause early damage to the pavement structure due to the additional stress on the pavement structure.The existing literature on the effect of uneven settlement of soft ground on the stress of pavement structure is still relatively few.The foundation soil is a historical product of natural geology.In practice,the soil often appears as heterogeneity.In the existing road structure mechanics,the foundation is generally analyzed as an elastic foundation.There is less research on the heterogeneity of the foundation,and less research on the heterogeneous settlement of the heterogeneous foundation.Therefore,the study of the influence of uneven foundation settlement on the additional stress of the pavement structure has a very positive significance in the design of the road surface.Based on the generalized Gibson foundation theory of heterogeneous settlement and the soil consolidation theory,this paper takes the Guang-Fo-Jiang Expressway Project as the engineering support,and adopts analytical and numerical analysis methods to study the additional stress caused by the uneven settlement of the foundation to the pavement structure.Impact,proposed the pavement design index and design method considering uneven settlement of foundation.The main results obtained are as follows:1.Aiming at the problem of laterally uneven subsidence of foundation commonly found in engineering,a generalized Gibson model for heterogeneous settlement of subgrade settlement is established.The Hankel transformation is used to solve the boundary value problem,and the integral solution of the problem is obtained.The influences of the heterogeneity parameter m,the differential settlement,the depth of uneven settlement and the uneven settlement width on the vertical displacement of the soil at various points were analyzed in detail.2.The inhomogeneous settlement of the generalized Gibson model is introduced into the road mechanics calculation theory.The integral solution of the viscoelastic thin plate and elastic layer problem on the generalized Gibson foundation under heterogeneous settlement is obtained.The effects of the heterogeneity parameter m,the depth of uneven settlement and the shear modulus of the elastic layer on the horizontal bending stress in the elastic layer under circular uniform symmetric loads are discussed in detail.The influence of structural additional stress provides theoretical support.3.The finite element model of consolidation settlement of soft soil foundation was established.The influence of lateral uneven settlement of subgrade on the deformation of subgrade was studied under different subgrade heights,subgrade soil elasticity,elastic modulus and pavement width,and the lateral unevenness of foundation under the influence of different factors was obtained.The relationship between settlement and subgrade deformation.4.A simplified finite element model of pavement additional stress calculation is established,and the influence of base parameters,cushion parameters,uneven settlement and pavement width on additional stress is discussed in detail,and the additional stress calculation formula of uneven settlement pavement under the comprehensive influence of various factors is obtained.5.Considering the influence of uneven settlement on the bending stress of the pavement,the horizontal bending stress caused by the uneven settlement and the bending tension caused by the load are superimposed to calculate the bending stress.The method for designing the pavement structure considering uneven settlement is proposed.