交通荷载作用下加筋土路基残余变形减小的机理分析

摘要

应用有限单元法对交通荷载作用下加筋土路基进行隐式动力分析,并基于累积塑性变形的计算和影响因素分析,揭示加筋减小路基土残余变形的机理.分析结果表明:对于级配碎石基层沥青混凝土路面,加筋改善路基表面的压应力分布,减小传递到路基表面的剪应力,加筋后路基土上部80cm范围内动偏应力大大减小,而动偏应力是引起路基残余变形的重要因素之一;另一方面,交通荷载作用下,路基土的累积塑性变形主要发生在路基上部100cm范围内.因此,加筋后路基土累积塑性变形的减小,主要是由于加筋减小交通荷载作用下路基土上部的动偏应力;土工格栅刚度越大,动偏应力减小越显著.%Reinforced and unreinforced subgrades under traffic loading were modeled by using implicit dynamic FEM.Through numerical calculation and influence factor analysis of the cumulative plastic deformation, the mechanism that the reinforcement can reduce the residual deformation of the subgrade was investigated.Analysis result shows that the reinforcement can improve the vertical compressive stress distribution, and decrease the shear stress on the surface of the subgrade of graded-broken-stone-based asphalt concrete pavement.The deviator stress on the upper 80cm part of the reinforced subgrade is reduced distinctively, which is one of the key factors that can lead to cumulative plastic deformation.On the other hand, the main cumulative plastic deformation is formed in the upper 100cm part of the subgrade under traffic loading.Therefore, the main reason for the decrease of cumulative plastic deformation of a reinforced subgrade is that the reinforcement can diminish the deviator stress on the upper part of the subgrade induced by traffic loading.The deviator stress would decrease with the increase of the stiffness of geogrid.