隧道衬砌病害地质雷达探测正演模拟与应用

Forward simulation of ground penetrating radar and its application to detection of tunnel lining diseases

国内大多数隧道都存在着不同程度的病害,其中诸如衬砌开裂、不密实、含有空洞和渗漏水等衬砌病害是隧道最常见的病害类型,严重影响行车安全。地质雷达(GPR)可以用来对隧道衬砌病害进行快速无损探测,但对于衬砌病害的解译十分依赖于探测人员的经验,很容易造成误判和漏判。因此,对隧道衬砌病害进行分类,并针对典型衬砌病害类型进行建模,利用时域有限差分(FDTD)法对衬砌病害模型进行地质雷达探测正演模拟,针对衬砌渗漏水和存在钢筋干扰等特殊情况,通过频谱分析对病害进行了定量识别,总结出典型衬砌病害的地质雷达探测解释准则,最后结合工程实例对衬砌病害进行了推断和解译。结果验证了衬砌病害地质雷达探测正演模拟和解释准则的可靠性。

Most tunnels in China have different degrees of diseases, such as lining cracking, imperfect, lining containing voids and lining water leakage, which seriously influence the traffic safety. Ground penetrating radar（GPR） is used to detect the tunnel lining diseases rapidly and nondestructively. However, the interpretations for lining diseases of GPR detection results strongly rely on the experience of GPR users, which to great extent leads to missing and even wrong judgments. In this study the tunnel lining diseases are classified, and the typical types of tunnel lining diseases are modeled. Finite-difference time-domain（FDTD） method is used to perform forward simulations of typical tunnel lining diseases. For special conditions of water leakage of lining and interference induced by steel reinforcement, the frequency spectrum analysis is used to quantitatively analyze these diseases. Interpretation rules of GPR detection for typical tunnel lining diseases are summarized and further applied to a real project example. The results show that the forward simulations and interpretation rules of GPR detection for typical tunnel lining diseases are reliable.