Test and Analysis of GPR Image Characteristics of Geometrical Morphology of Different Voids in the Concrete Test Block
According to the condition of voids in tunnel unreinforced linings at the construction site,a physical model of a full-size concrete test block was constructed and voids of different geometric shapes were set up to simulate the void de-fects in the unreinforced lining.Ground penetrating radar(GPR)was used to detect the void defect data under different ages,different antenna frequencies,and different defect comparisons,then the characteristics of the GPR image were tested and analyzed.Results demonstrate that the optimal antenna frequency for void detection of the unreinforced lining is 800 MHz,the optimal detection time is about the 17th day,and the maximum amplitude AT and electromagnetic wave energy ET can be used as important characteristic parameters for voids identification in the early days.The relationship between the electromagnetic wave amplitude properties of voids in different shapes and the concrete age shows a"W"shaped curve rule.When void and uncompacted defects exist at the same time,the AT is more suitable for the identifica-tion of uncompacted defects.This study can provide a theoretical basis for the identification of tunnel unreinforced lining voids and uncompacted defects,and provide a reference for the selection of the detection time and antenna of tunnel un-reinforced lining voids in the construction site.
GPRphysical model experimentsunreinforced liningvoidscharacteristic testing and analysis
万方数据
维普
