铁路隧道复合式衬砌地质雷达检测模拟试验研究

Simulation tests on GPR detection of composite linings of railway tunnels

针对铁路隧道复合式衬砌存在的复杂病害,按足尺寸施做复合式衬砌试件模型,进行地质雷达检测模拟试验研究。模拟试验结果表明:地质雷达扫描图中能够反映各种预先设置的衬砌背后空洞、回填不密实等衬砌异常情况,并且具有强反射区、同相轴连续等特征;二次衬砌厚度检测精度与衬砌相对介电常数密切相关,在准确测定相对介电常数的条件下,衬砌厚度能够定量分析,精度可达±4 cm;相对介电常数宜取多个标定点的平均值,并宜对素混凝土衬砌和钢筋混凝土衬砌分别测定。模拟试验结果对实际工程地质雷达检测及其结果分析具有一定的参考价值。

With regard to complex diseases of composite linings of railway tunnels, a specimen model for composite linings in terms of the whole size is established, and the ground penetrating radar （GPR） detection is studied based on simulation tests. The test results show that lining abnormalities can be reflected, which are pre-set in the GPR scan, with the typical characteristics of the strong reflection zone and a continuous phase axis. The measurement accuracy of the secondary lining thickness relates to the relative dielectric, the thickness of the secondary linings can be analyzed by quantitative analysis under the conditions that the relative dielectric of layer is accurately determined, and the accuracy can reach -4- 4cm. The relative dielectric should take the average number of gauge point, and the linings of plain concrete and reinforced concrete should be determined separately. The results will be valuable for the results of GPR detection in actual engineering.