Strain-based condition evaluation has garnered as a crucial method for the structural health monitoring (SHM) of large-scale engineering structures. The use of traditional wired strain sensors becomes tedious and time-consuming due to their complex wiring operation, more workload, and instrumentation cost to collect sufficient data for condition state evaluation, especially for large-scale engineering structures. The advent of wireless and passive RFID technologies with high efficiency and inexpensive hardware equipment has brought a new era of next-generation intelligent strain monitoring systems for engineering structures. Thus, this study systematically summarizes the recent research progress of cutting-edge RFID strain sensing technologies. Firstly, this study introduces the importance of structural health monitoring and strain sensing. Then, RFID technology is demonstrated including RFID technology’s basic working principle and system component composition. Further, the design and application of various kinds of RFID strain sensors in SHM are presented including passive RFID strain sensing technology, active RFID strain sensing technology, semi-passive RFID strain sensing technology, Ultra High-frequency RFID strain sensing technology, chipless RFID strain sensing technology, and wireless strain sensing based on multi-sensory RFID system, etc., expounding their advantages, disadvantages, and application status. To the authors’ knowledge, the study initially provides a systematic comprehensive review of a suite of RFID strain sensing technology that has been developed in recent years within the context of structural health monitoring.
30 September 2009 in Procedia Earth and Planetary Science
This paper presents the concept of synergetic support with a comprehensive design method based on the existing support theories and engineering practices. The synergetic support is different from the common combined support method as it can fully mobilize all the components to bring active support and get the effect of 1+1≥2. The numerical simulation was used to study the pre-stress cooperation between bolts and cables which is the main part of the synergetic design method. Extensive simulations were made on the performance of the individual and synergetic bolts and cables with different pre-stress forces. The simulation results show that, even high-strength bolts can’t offer active support without any pre-stress, therefore high-strength bolts should work with prestress. The proper match between prestress bolts and cables can fully mobilize their individual performances and eventually get to the synergetic support.
To learn more about the problem of blast weakening in shallow-buried and extra-thick coal seams, Panjin coal mine was used to provide the engineering background for this study. The influence of blast weakening technology on the vibration of ground buildings was investigated. Based on monitoring the vibration data from the final 400 m of the working face, we established the Sadovsky formula for this coal mine through regression. The maximum safe charge of one blast at different distances was obtained. A numerical model was established and compared with field monitoring data to verify its accuracy. This numerical model was used to analyze the influence of blast weakening vibrations on ground buildings during the final mining stage. Finally, the maximum safe charge for one blast at advancing distances from the working face was derived based on numerical calculation results. It was compared with the maximum safe charge obtained from field measurements. The results show that both exhibit significant consistency, and the maximum safe charge of one blast decreases as the working face advances. In addition, the peak vibration velocity at each monitoring point does not exceed 0.2 cm/s for the remaining 400 m of the measured working face, which is lower than the allowable safety value for blasting vibrations. In the numerical simulation of the final mining stage at 200 m, the ground vibration velocity is largest for the district office, second-largest for the chimney, and smallest for the science and technology building. The maximum vibration velocity and effective stress in the three directions of the three buildings are within the allowable range, indicating that the buildings remained in a safe state.