软基差异沉降对夹层路面结构的影响分析

软土地基上路基的不均匀沉降变形加速了沥青路面结构的早期破坏;由于国内90%以上的高速公路都是常规的半刚性基层沥青路面结构,不能很好地消散不均匀沉降产生的附加应力,因此有必要提出新的适应软土地基上的路面结构形式。依托淮盐高速公路中设有级配碎石夹层结构的试验段,采用ABAQUS非线性有限元分析了该路面结构在不均匀沉降时的底基层和应力控制层层底的附加应力。结果表明,不均匀沉降增大时,底基层和应力控制层的水平向附加应力都呈线性增大;底基层厚度一定时,底基层模量越大,其层底拉应力越大,而应力控制层水平向附加应力明显减小,但是底基层厚度不宜太厚;相对于半刚性基层路面,设有级配碎石夹层结构的路面有更大的强度储备,更能适应软基不均匀沉降。所得结论对今后软土地基上的路面结构设计有一定的指导意义。

Analysis of the Effect of Soft Ground with Differential Settlements on Sandwich Pavement Structure

Differential settlement of embankment on soft clay accelerates incipient failure of pavement structure.More than 90%(expressways) are conventional semi-rigid base asphalt pavement structure in China which can not dissipate additional stress effectively,therefore,some new pavement structures are proposed which are adaptable to differential settlement on soft clay.Adopting the general-purpose non-linear finite element ABAQUS,a new sandwich pavement structure which is composed of unbound graded aggregate is(analyzed),based on the test road section of Huai-Yan expressway.The test results show that the horizontal stress of the base course and the stress control layer would increase linearly with the growth of the differential settlements;when the base course thickness in constant with greater modulus,the tensile stress at its bottom would be greater with additional horizontal stress in the control layer reduced(conspicuously),but the thickness of the base course should not be too great;and that the new pavement structure is more adaptable to differential settlement than semi-rigid base pavement structure due to its greater strength reserve.These conclusions make contribution to the expressway design on similar soft clay.