机场道面及其下部地基脱空的测试方法
Test methods of airport pavement and subjacent foundation void

分析了机场跑道重锤式弯沉仪、探地雷达、面波与映像的测试结果,判别了机场刚性道面板底部脱空、下部地基沉陷与地基空洞变形,对比了不同脱空深度和位置下的波谱特点,研究了基于应力波与电磁波的道面脱空测试方法的有效性与优越性,并对测试精度进行现场钻芯验证。验证结果表明:传统重锤式弯沉仪测试数据为道面表层荷载位移,无法反映跑道道面板底部土基沉陷变形与脱空缺陷; 面波测试深度较大,采样数据可反映道面板下部地基变形与脱空状态; 映像方法测试道面板底部反射波性状,可实现对道面板结构层底部脱空的判定; 以上3种测试方法均为间隔采样,受采样点数目限制,对跑道整体状态代表性不足,无法克服由采样点间距导致的评价误差; 探地雷达测试方法可实现连续状态测试,测试范围覆盖率为100%,且雷达测试数据与传统测试数据符合率为95%,并经8样本点钻芯试验验证孔底脱空测试精度为87.5%,但雷达测试结果对脱空的量化分析不足,需依托面波测试与映像测试结果对脱空测试结果进行有效验证。
The test results of heavy weight deflectometer(HWD), ground penetrating radar, surface wave and image were compared and analyzed contrastively, and the bottom voids of airport rigid pavement slab, foundation subsidence and void cavity deformation were identified. The spectrum characteristics at different void depths and positions were compared, the effectiveness and superiority of each pavement void test method based on stress wave and electromagnetic wave were studied, and the test accuracy was verified by field core-drilling test. Verification result indicates that the test data of traditional HWD are pavement surface displacements under load, and do not reflect the foundation subsidence and void deformation under pavement slab. The subsidence and void deformation in soil foundation can be reflected by surface wave test data, because the test depth is greater. The bottom void cavity under pavement slab can be determined by analyzing the properties of return wave from pavement slab bottom by using image test method. But the interval sampling is adopted by above three methods, field test is limited by the number of sampling points, which results in that the runway integrity representativeness of test data is insufficient, and the evaluation error from sampling interval can not be overcome. The continuous and large scale test with ground penetrating radar can be conducted, the test coverage is 100%, the coincidence rate of void between radar data and HWD data is 95%, and the test accuracy of void in hole bottom is 87.5% by core-drilling test with 8 sample points. However, the quantitative analysis on void with radar is insufficient, surface wave test and image test are proved to be effective supplement and verification to pavement void testing and soil foundation cavity testing with radar. 6 tabs, 21 figs, 25 refs