沥青路面层间粘结性能的黏弹性有限元分析

Viscoelasticity finite element analysis of interface bonding behaviors of asphalt pavement

为深入剖析半刚性基层沥青路面层间粘结性能,基于黏弹性理论,建立三维有限元模型研究不同层间接触状态下基面层之间的剪应力分布.考虑实际工程情况,引入夹层,应用层间剪力定量描述其与时间的关系,研究夹层存在薄弱粘结和夹层参数对层间粘结性能的影响.结果表明:随着层间摩擦系数的减小,层间剪应力逐渐减小,沿路宽方向的剪应力较大,层间接触不连续时,剪应力存在突变;引入虚拟夹层后,随着加载时间的增加,沿行车方向的层间剪力逐渐增大,沿路宽方向的层间剪力逐渐减小;由于夹层存在薄弱粘结,剪力向薄弱粘结周围扩展,剪力最大值也有一定幅度的增加;随着夹层抗压模量的增大,层间剪力最大值逐渐增大;层间剪力随着夹层厚度的增加而增大,且增大趋势接近线性变化.分析结果表明,沿路宽方向的层间剪应力对路面力学响应起着重要的作用,在路面设计中应对基面层间的抗剪性能给与足够的重视,需要设置粘结层来改善层间接触状态,并采取适当的方法来消除夹层薄弱粘结和优化夹层设计参数.

To analyze interface bonding behaviors of semi-rigid base asphalt pavement, the shear stress distribution between asphalt layer and base under different interfacial contact conditions was studied, then a suppositional interlayer inserted as practical engineering applied one was taken into account, moreover interfacial shear force as an indicator used to characterize the relation with time quantitatively, and the effects of interlayer with weak bonding and its parameters on interface bonding behaviors were analyzed as well by using three-dimensional finite element model based on viscoelasticity mechanics. Results indicate that the interfacial shear stress decreases with the decrease of the interfacial friction coefficient, and shear stress value along the road breadth direction （longitude） is bigger, comparing with traffic direction （latitude）, furthermore, shear stress appears catastrophic where the discontinuity of interlayer exists. The latitude interface shear force increases and the longitude interface shear force decreases with time increasing while the suppositional interlayer is inserted into the model. Then the shear forces expands around the weak bonding, and the maximum shear force value rises to a certain extent due to the interlayer with weak bonding, moreover, the maximum shear force value increases as well as compressive modulus and thickness of interlayer increasing. The analysis shows that longitude interface shear force has considerable influence on the mechanics response of the pavement, therefore the resistance to the interracial shear deformation between asphalt layer and base should be an important index in the design of asphalt pavement, and bonding interlayer should be set up to improve the contact conditions, and appropriate measures should be adopted to remove the weak bonding and optimize the design parameters of interlayer.