Autonomous Crack Displacement Monitoring of a Residence Near a QuarryPublic Deposited
This paper describes the technology and methods deployed in the continuous autonomous remote monitoring of cracks in interior and exterior walls of a residence near a limestone quarry. The objective is to quantitatively compare crack response due to blast-induced ground motion to that induced by diurnal temperature changes, weather fronts, occupant activity, and other phenomena. The remote monitoring and communication technology developed to obtain and disseminate crack response data for this study may provide the means to mitigate the effect of public concerns about potential impacts of ground vibrations inherent in construction and production of raw materials; it is critical to address these concerns because subsequent litigation may result in delays and increased costs. This communication technology consists of four components: displacement sensors with microinch resolution, autonomous computer control, robust high-speed communication, and Internet display of results. Displacement transducers can be employed to compare the long-term (weather) and dynamic (ground motion, occupant activity, and other events) response of cracks. Comparison of the response of the same cracks to both long-term and dynamic phenomena can be employed to distinguish between the large “silent” effects of weather and the smaller but “noisy” effects of blast-induced ground motion. Data from these sensors are electronically recorded and communicated back to a central digital repository for display and analysis. Throughout the study, it was found that the crack response to long-term weather effects was at least one order of magnitude greater than the response to blast-induced ground motion. Crack response to everyday household events such as closing doors or pounding on walls was generally greater than or similar to response to blast-induced ground motion. The remote monitoring system described operates continuously and autonomously. Data are made available for review in near-real time via a password-protected web site. It is hoped that unmoderated, ondemand interaction with the measurements will allow greater public involvement with the vibration monitoring program and help assuage fears of damage to nearby property.
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