波音747型飞机跑道滑行力学响应
Mechanical responses of Boeing 747 running on runways

根据丹佛国际机场跑道大量实测的道面应变与弯沉,分析了波音747型飞机滑行时道面不同位置弯沉和应变的主要特征,研究了不同接缝传力特性、不同位置的残留变形与应变率。分析结果表明:板边与板中有2个应变峰值,对应于轮轴个数; 板横缝方向(与飞机滑行方向垂直)不存在反向应变,而纵缝方向(与飞机滑行方向平行)存在2次拉压应变,纵缝板边底部轮轴间的应变峰值回复量显著,易发生开裂和疲劳破坏,其底部应变峰值和应变峰值回复量分别是板边顶部的1.2倍和2.5倍; 飞机滑行时接缝处的应变率最大,最大拉伸和压缩应变率分别为9.1×10-4 s-1和7.6×10-4 s-1,在混凝土板中引起的应变率属于准静态应变率,忽略其对混凝土板变形的影响; 板中弯沉为单峰值曲线,而板角与横缝板边弯沉为双峰值曲线; 在同一板中,板角处的相对残留变形最大,板中处最小,板角处的相对残留变形率是板中处的2.60～4.59倍,相比于其他位置,板角更容易与基层发生脱空; 铰缝传力系数接近1,假缝与铰缝相比传力效率较低,其传力特性具有明显的方向性,而铰缝传力没有明显的方向性。
Based on the large amounts of measured strains and deflections of runway pavement at Denver International Airport, the main characteristics of deflections and strains at different positions of pavement were analyzed when Boeing 747 was running on runway, and the load transfer capacities of different joints, the residual deformations and strain rates of pavement at the typical positions were researched. Analysis result shows that the edge and middle of slab have 2 strain peaks respectively, which corresponds with the number of aircraft’s main gear axles. The transverse strain(perpendicular to the running direction of aircraft)only has one type, while the longitudinal strain(parallel to the running direction of aircraft)shows 2 times’ transformation between tension and compression. The peak-strain recovery between gear axles at the bottom of longitudinal joint edge is significant, its peak strain and peak-strain recovery are 1.2 times and 2.5 times as much as the values at the top of longitudinal joint edge respectively, which means more prone to cracking and fatigue damage. When the aircraft is running, the maximum strain rates occur at the joint, and the maximum tensile and compressive strain rates are 9.1×10-4 s-1and 7.6×10-4 s-1 respectively, and belong to quasi-static strain rate, so their impact on the deformation of concrete slab are ignored. The deflection curves at the slab’s middle have 1 peak, but there are 2 peaks at the slab’s corner and transverse joint edge. The relative residual deformation at corner of slab is largest, the deformation at the middle of slab is least, the relative residual deformation rate at the corner of slab is 2.60-4.59 times as large as the value at the middle of slab, and compared with other locations, the corner more easily occurs void with base. The load-transferred coefficient of hinged joint is about 1, the load-transferred coefficient of dummy joint is lower compared with hinged joint, the load-transferred characteristic of dummy joint has directionality, but the load-transferred characteristic of hinged joint is non-directional. 3 tabs, 12