硫酸盐盐渍化道路横向隆起的力学响应分析

Analysis on Mechanical Response of Transverse Uplift of Sulphate Salinized Pavement

针对沙漠区沥青混凝土道路因路基土硫酸盐盐渍化,土体膨胀所导致的路面横向隆起病害,为了研究病害不同发展阶段路面结构的受力特性及破坏形式,了解该类病害影响下路面结构所能承受的临界应力和破坏时隆起变形的临界挠度,以发生横向隆起病害的路面实体为研究对象,基于复合材料力学与弹性力学理论,结合病害实体基本特征及分布情况,将路面结构抽象简化为一层间接触良好、变形连续的整体式层状结构,构建了路面结构在路基盐胀作用及其自重影响下发生横向隆起病害的力学模型,推导了路面结构在路基盐胀作用及其自重影响下隆起变形的挠度方程。在此基础上,进一步求得了路面结构在上述作用下的应力、应变公式及整体式双层梁结构的刚度计算公式。之后,结合具体实例,分析了不同盐胀作用下,基层、面层的最大拉应力和挠度变化规律。根据路面结构参数与面层、基层的抗拉强度,通过所建力学模型中应力公式可判别在盐胀作用下路面结构基层、面层发生结构性破坏的时序。同时,对于既定参数的路面结构,利用模型中挠曲变形公式,可建立不发生由盐胀引起路面结构层结构性破坏所能承受的临界隆起高度和临界盐胀作用,有利于指导沥青混凝土道路盐渍化病害防治与路面结构组成设计。

Aiming at the transverse uplift disease occurred in asphalt concrete pavement in desert area which caused by the expansion of the sulfate salinization subgrade, in order to study the stress characteristics and failure modes of the pavement structure at different disease development stages, and figure out the critical stress and the critical deflection of uplift deformation at failure that the pavement can bear under the influence of the disease, taking the pavement entity which has occurred transverse uplift disease as the research object, combining with the basic characteristics and distribution of diseased entity, and under the assumption that the pavement structure is simplified as an integral layered structure with well contact and continuous deformation, a transverse uplift disease mechanical model of the pavement structure subjected to the subgrade salt expansion action and its gravity is built based on the theory of compound material mechanics and the elastic mechanics, and the deflection equation of the pavement structure under the salt expansion action and its gravity is derived. On this basis, the formulas for calculating the stress and strain of the pavement structure under the abovementioned actions and the stiffness formula of the integral double - layer beam structure are obtained. Afterwards, combining with the specific instance, the maximum tensile stress and the deflection change laws of the base and surface subjected to different salt expansion action are analyzed. According to the pavement structure parameters and the tensile stress of the base and the surface, the destruction time sequence of base and surface under the action of salt expansion are determined through the stress formula in the established mechanical model. Meanwhile, for the pavement structure with given parameters, the critical uplift height and the critical salt expansion action that the pavement structure can bear which not occur structural destruction caused by the salt expansion action can be determined by utilizing the deflection formula in the model. It is benefit to guide the prevention and the treatment of salinization disease of asphalt concrete pavement and the design of pavement structure constitution.