Dynamic response analysis of airport pavements during aircraft taxiing for evaluating pavement bearing capacity

Abstract

In this paper, we propose a new method to analyze airport pavement bearing capacity using vibration in runways during aircraft taxiing. The new method overcomes shortcomings of existing tests, such as flight suspension and simulated loading. Between aircraft take-off and landing, acceleration sensors are arranged on the surface of the pavement far from the centerline, and the in-situ responses of the pavement under aircraft loads are collected during aircraft operations. The fundamental frequencies of the pavement are obtained by fast Fourier transformation of the measured accelerations, and are used to modify the parameters of a pavement finite element model built according to a design blueprint. By comparing the fundamental frequencies of the measured and calculated signals, the soil modulus is back-calculated. To implement this test method and ensure the accuracy of bearing capacity evaluation, aircraft dynamic loads are obtained by solving dynamic balance equations of the aircraft-pavement coupled system, and the vibration response of the pavement and sensitivity analysis of the fundamental frequencies are introduced. The results show that the fundamental frequencies at the center of the pavement are basically the same as those at the far side on the cross section; the fundamental frequencies in the depth direction remain constant, but the amplitude of the frequency spectrum decreases. The effect of the soil resilient modulus on the vibration frequency is most significant. The fundamental frequency increases from 6.02 to 10.55 Hz when the soil dynamic resilient modulus changes from 91 to 303 MPa. The effects of surface thickness and base thickness on the vibration frequency are less significant, and there is minimal influence when changing the dynamic elastic moduli of the surface layer or base layer. Field test results indicate the efficacy of the method of vibration measurement at the pavement surface to estimate the layer modulus of airport pavement.

摘要

目 的

目前的道面承载力评价需要在航班结束后进行, 存在难以找到合适时间进行测试和模拟加载的缺陷. 本文旨在通过分析飞机滑行过程中道面的振动响应, 建立道面振动基频与承载力的关系, 以实现飞机运行情况下道面承载力评价.

创新点

1. 根据飞机的真实运营情况, 考虑升力的影响, 确定了飞机的随机动荷载; 2. 分析了道面全宽度及 11 m 深度内的振动响应, 确定了振动响应变化规律以及对振动基频影响最为显著的因素.

方 法

1. 通过理论推导, 建立飞机-道面系统平衡方程; 考虑升力的作用, 并结合边界条件, 求解飞机的动荷载. 2. 通过仿真模拟, 分析了全部道面范围内振动基频的变化规律及道面远端振动基频的影响因素. 3. 通过现场测试, 验证测试方法的有效性和可行性.

结 论

1. 当飞机的滑行速度超过 15 m/s 时, 在升力的影响下, 飞机的随机动荷载随着飞机滑行速度的增加持续下降; 当飞机的滑行速度固定时, 随着道面平整度变差, 动荷载增大. 2. 沿横断面方向, 道面中心处的振动基频仅比远端大 2%; 从面层至土基, 振动基频不变, 仅振幅逐渐减小. 3. 土基动回弹模量对道面远端振动基频的影响最为显著, 可达 43% 左右, 其次是面层厚度与基层厚度, 而面层弹性模量与基层回弹模量对振动基频的影响最小.