地质雷达检测隧道衬砌常见病害模型实验研究

建立了由素混凝土、单层钢筋网及双层钢筋网3个区段组成的隧道衬砌试验模型,模型中布设了常见病害（空洞、空洞积水和混凝土析水）。模型自然养护28天,运用地质雷达对衬砌模型进行检测。对比隧道衬砌模型的地质雷达剖面图与实际的衬砌布设情况,可得结论：地质雷达检测对钢筋的存在反应敏感;双层钢筋网检测存在一定程度的缺陷;病害复杂（叠加）处检测图像辨识准确度较差;钢筋网的存在对其上下方病害的检测存在一定的影响;空洞积水的反射特征明显,易于识别;地质雷达（配800 MHz天线）的检测精度约在50 mm范围内,不能完成小尺寸空洞的检测。这为隧道衬砌常见病害的检测识别提供了一定的经验依据,并对隧道衬砌中双层钢筋网内病害和小尺度病害的检测做了初步探讨和研究。

Experimental Study on Common Disease Detection of Tunnel Lining with GPR

In order to study the application of geological penetrating radar （GPR） in tunnel lining detection elaborately, this paper establishes a test model comprised of three different supporting sections （plain concrete, single-layer rebar and double-layer rebar）, which formulates such normal damages as voids, voids filled with water and the concrete bleeding. The GPR profiles were obtained via processing the health monitoring signals with the special geological radar software. Comparing the GPR images with the actual layout settings in the tunnel lining, it finds that the GPR is impressible to steel, while it is inaccurate for the double rebar. And the reflection images for the common diseases are difficult to identify due to the steels in the tunnel liner. For the void, the reflection image is easy to identify when it is filled with water, while it is difficult when the diameter of the voids is 50 mm. To some degree, the results are significant for further researches of the GPR in tunnel lining common disease detection.