水工隧洞钢管衬砌脱空超声检测方法研究.

Steel pipe lining is a common support method for hydraulic engineering tunnels. It is very important to apply advanced technology to carry out void detection of steel pipe lining for project quality evaluation. In this paper, the longitudinal wave reflection coefficients of the three interfaces between steel and water, concrete and air were calculated, and the amplitude and phase variation characteristics of the reflection coefficients with the incident angle were analyzed. Through theoretical analysis, a data processing and analysis method by using the amplitude ratio of ultrasonic multiple reflection waves to detect voids was proposed. Concrete models with a thickness of 1.6 cm and 3.0 cm steel plates were made, and the models were tested with two types of 2.5 MHz probes. The results show that the reflected wave amplitude in the void area is relatively higher, which verifies the theoretical results of this paper. The pulse echo method is used for comparative detection, and the results show that the method has a certain detection effect. Since the actual impedance of the concrete cemented with the bottom of the steel plate is relatively lower, it is recommended to divide a larger detection unit for detection of a large amount of data to improve the accuraey of void discrimination.. [ABSTRACT FROM AUTHOR]