雷达探测隧道壁后空洞的现场验证及空洞影响分析

针对王市岭隧道隧改路工程,采用探地雷达检测衬砌壁后空洞,并进行钻孔取芯验证,结果表明探地雷达用于壁后空洞检测可行且具有较高的可信度。为系统分析壁后空洞对隧道结构的影响,基于现场原位测试数据,建立了连拱隧道的三维快速拉格朗日有限差分模型。数值分析结果表明,拱顶、拱肩和边墙部位的空洞均会导致衬砌局部产生拉压应力集中,应力集中程度受空洞位置与尺寸的双重影响。在竖向地应力为主的条件下,拱肩部位的空洞对衬砌危害最大,易导致拱肩上侧部位出现较大的应力集中,因此在隧道壁后空洞病害检测时应重点考虑拱肩部位。

In situ Verification of Voids Behind Tunnel Lining Detected by  Ground Penetrating Radar and Numerical Analysis of Influence of  Voids on Tunnel Structure

The application of ground penetrating radar to the detection of voids behind Wangshiling Tunnel lining and the core drilling results show that the ground penetrating radar is feasible and reliable. A 3D fast Lagrangian finite difference analysis model of twin arch tunnel is established based on in situ testing data, so as to analyze the influence of voids behind tunnel lining on tunnel structure. The numerically analytical results show that: 1) The local concentrated tensile stress would be resulted due to the voids above crown top and behind arch shoulders and sidewall. 2) The concentration degree of tensile stress is affected by locations and sizes of voids. Under the condition of vertical ground stress, the voids behind arch shoulders are the most dangerous and can induce large stress concentration above arch shoulders. As a result, more attention should be paid to detection of voids behind arch shoulders.