地下连续墙缺陷的跨孔电磁波层析成像研究

Research on Electromagnetic Wave Tomography for Underground Diaphragm Wall

由于工程特点及施工原因,城建和水利工程中的地下连续墙墙体可能出现断裂、裂缝、空洞、夹泥、离析等质量缺陷与病害隐患问题,危及工程安全。针对连续墙中缺陷常呈块状分布的情况,笔者将最小支撑聚焦泛函应用于电磁波走时层析成像中,对地下连续墙缺陷模型的成像效果进行了研究。与最小模型泛函和最光滑泛函的成像效果相比,该方法能够较好地突出连续墙中缺陷的边界,缺陷的空间展布形态更加接近于真实模型。针对地下连续墙典型缺陷的物理模型,该方法取得了理想的成像结果,准确地揭示出了缺陷的形态和类型。基于最小支撑聚焦泛函的电磁波走时层析为地下连续墙缺陷的检测提供了一个便捷、可靠的方法。

Many kinds of defects and hidden diseases,including cavities,cracks,mud and segregation of concrete can be frequently found in underground diaphragm wall because of the engineering characteristics and construction technology. It might lead to serious engineering safety problems. Considering the block characteristics of most defects in the underground diaphragm wall,electromagnetic wave tomography based on the minimum supported focusing functional was proposed and discussed via numerical simulation. Compared with the tomography effects of the minimum model functional and the maximum smoothness functional,the minimum supported focusing functional can be more efficient in highlighting the boundary between the defects and the background. Furthermore,the new proposal can obtain the more exact inversion result which is more close to the real model. The proposal method was also applied to a physical model,the tomography result reveals that it is possible to locate the defect and give exact relative dielectric constant. It therefore provides a convenient and reliable approach for the defect detection of the underground diaphragm wall.