title: Measurement of the Length of Installed Rock Bolt Based on Stress Wave Reflection by Using a Giant Magnetostrictive (GMS) Actuator and a PZT Sensor.
abstract: Rock bolts, as a type of reinforcing element, are widely adopted in underground excavations and civil engineering structures. Given the importance of rock bolts, the research outlined in this paper attempts to develop a portable non-destructive evaluation method for assessing the length of installed rock bolts for inspection purposes. Traditionally, piezoelectric elements or hammer impacts were used to perform non-destructive evaluation of rock bolts. However, such methods suffered from many major issues, such as the weak energy generated and the requirement for permanent installation for piezoelectric elements, and the inconsistency of wave generation for hammer impact. In this paper, we proposed a portable device for the non-destructive evaluation of rock bolt conditions based on a giant magnetostrictive (GMS) actuator. The GMS actuator generates enough energy to ensure multiple reflections of the stress waves along the rock bolt and a lead zirconate titantate (PZT) sensor is used to detect the reflected waves. A new integrated procedure that involves correlation analysis, wavelet denoising, and Hilbert transform was proposed to process the multiple reflection signals to determine the length of an installed rock bolt. The experimental results from a lab test and field tests showed that, by analyzing the instant phase of the periodic reflections of the stress wave generated by the GMS transducer, the length of an embedded rock bolt can be accurately determined.
authors.affiliation: Electronics and Information School, Yangtze University, Jingzhou 434023, China. luomingzh@163.com.
authors.forename: Mingzhang
authors.initials: M
authors.lastname: Luo
authors.affiliation: Department of Mechanical Engineering, University of Houston, Houston, TX 77004, USA. wli27@uh.edu.|School of Civil Engineering, Dalian University of Technology, Dalian 116023, China. wli27@uh.edu.
authors.forename: Weijie
authors.initials: W
authors.lastname: Li
authors.affiliation: Key Laboratory of Transportation Tunnel Engineering, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, China. ahbowang@home.swjtu.edu.cn.
authors.forename: Bo
authors.initials: B
authors.lastname: Wang
authors.affiliation: Electronics and Information School, Yangtze University, Jingzhou 434023, China. jpufqq@yangtzeu.edu.cn.
authors.forename: Qingqing
authors.initials: Q
authors.lastname: Fu
authors.affiliation: Department of Mechanical Engineering, University of Houston, Houston, TX 77004, USA. gsong@uh.edu.|School of Civil Engineering, Dalian University of Technology, Dalian 116023, China. gsong@uh.edu.
authors.forename: Gangbing
authors.initials: G
authors.lastname: Song
keywords: determination of installed rock bolt length; giant magnetostrictive actuator; instant phases; non-destructive evaluation; rock bolt monitoring; stress wave reflection