机场水泥道面接缝位移及嵌缝材料结构应力

Displacement of airport concrete pavement joints and structural stress of sealants

为深入研究机场道面接缝缝槽的水平和竖向位移对于嵌缝材料黏附性失效和嵌缝材料挤出的影响，采用有限元分析的手段，计算机场水泥道面接缝缝槽在环境温度和湿度变化下引起的缝槽水平位移量，以及飞机荷载作用引起的缝槽竖向位移量，并与实际观测数据进行对比分析。计算表明，机场水泥道面接缝缝槽水平位移量为2．2mm左右，拉伸应变量可取为25％，与公路水泥路面基本相当；接缝缝槽的竖向位移量处于0.25～0.61mm，剪切应变量处于3．1％～7．7％，较公路水泥路面大一些。选择包含弹簧单元及Kelvin模型的三参数固体模型描述嵌缝材料的流变特性，通过拉伸松弛实验实际测定3种典型嵌缝材料的弹簧系数和黏壶系数，利用缝槽内嵌缝材料拉伸应力和剪切应力的简化计算公式，计算3种典型嵌缝材料极限状态下的结构应力，结果表明，嵌缝材料的结构应力主要来自于接缝水平位移所引起的拉伸应力，剪切应力与接缝传荷能力的变化密切相关。

To study the influence of horizontal and vertical displacements of joint on the cohesion failure and extrusion of the sealants in rigid pavement of airports, the displacement of the joint and structural stress of the sealants were researched. Horizontal displacement caused by environmental temperature ＆ humidity and vertical displancement caused by airplane loads were calculated separately by the finite element methods, and the data of in-situ were compared with these calculation results. It is suggested that about 2.2 mm （corresponding to 25% tensile strain） of the horizontal displacement and 0.25-0.61 mm （corresponding to 3.1%-7.7%shear strain） of the vertical displacement are reasonable as the parameters for calculating the structural stress of sealants in concrete pavement joints. The model containing of a spring element and a Kelvin model was used for depicting the sealants viscoelasticity performance, and three representative sealants were tested in order to achieve the coefficient of two springs and one dashpot by the stress relaxation experiments. Using the simplified tensile and shear stress calculation formula, the structural stresses of the three representative sealants were calculated, and it shows that the stress of sealants mainly comes from the joint horizontal displacement, and that shear stress is closely related to the change of the joint load transfer ability.