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A platform for research: civil engineering, architecture and urbanism
Instrumentation and Monitoring for Forensic Geotechnical Engineering
Instrumentation plays an important role in forensic geotechnical engineering. In soil mechanics, there are at least several reasons or mechanisms to explain a problematic phenomenon. The scientific facts that were recorded by instrumentation during the construction and/or post-construction give a direction to select one of several possible hypotheses. Two case histories are presented to show the effects of instrumentation upon the forensic investigation of the failure of geotechnical constructions. One is Teton Dam, Idaho in the U.S.A. that was earthen dam and failed during the first filling stage in 1976. Some conclusions were given by Independent Panel to review the failure; however, Teton Dam has been providing endless long debate because of not enough monitored data to rely on. Another one is Nicoll Highway Collapse that was caused by failure of retaining wall during subway construction in Singapore in 2004. In this second case, monitored records of the deflection of retaining wall gave very important information. From the seventh excavation step, deflection of wall at south side became much larger than at north side. One-sided deformation was due to the inclined dense gravel layer toward south below the soft layer and deeper soft soil that differed from the initial design of horizontal layer condition. After the failure, it was confirmed thicker soft soil layer in the south compared to north side by boring study. If the retaining wall had failed without knowing different performance between these walls, it might be much work needed to reach the right conclusion. Instruments and sensors in geotechnical engineering are briefly reviewed. In recent decades, new technologies were introduced to sensor and instrumentation in geotechnical engineering. Among these innovative instruments, two techniques are introduced. Carrier Phase Tracking GPS for measuring displacement between reference GPS receiver and target GPS receiver with a high accuracy of displacement of 2–5 mm. BOTDR (Brillouin Optical Fiber Reflectometer) is another cutting edge technology that provides strain and temperature. Technical basic knowledge of these instruments is explained to understand the principle that is useful not only to follow but also to take advantage of the next generation of instrumentation becoming to prevail at present and in near future.
Instrumentation and Monitoring for Forensic Geotechnical Engineering
Instrumentation plays an important role in forensic geotechnical engineering. In soil mechanics, there are at least several reasons or mechanisms to explain a problematic phenomenon. The scientific facts that were recorded by instrumentation during the construction and/or post-construction give a direction to select one of several possible hypotheses. Two case histories are presented to show the effects of instrumentation upon the forensic investigation of the failure of geotechnical constructions. One is Teton Dam, Idaho in the U.S.A. that was earthen dam and failed during the first filling stage in 1976. Some conclusions were given by Independent Panel to review the failure; however, Teton Dam has been providing endless long debate because of not enough monitored data to rely on. Another one is Nicoll Highway Collapse that was caused by failure of retaining wall during subway construction in Singapore in 2004. In this second case, monitored records of the deflection of retaining wall gave very important information. From the seventh excavation step, deflection of wall at south side became much larger than at north side. One-sided deformation was due to the inclined dense gravel layer toward south below the soft layer and deeper soft soil that differed from the initial design of horizontal layer condition. After the failure, it was confirmed thicker soft soil layer in the south compared to north side by boring study. If the retaining wall had failed without knowing different performance between these walls, it might be much work needed to reach the right conclusion. Instruments and sensors in geotechnical engineering are briefly reviewed. In recent decades, new technologies were introduced to sensor and instrumentation in geotechnical engineering. Among these innovative instruments, two techniques are introduced. Carrier Phase Tracking GPS for measuring displacement between reference GPS receiver and target GPS receiver with a high accuracy of displacement of 2–5 mm. BOTDR (Brillouin Optical Fiber Reflectometer) is another cutting edge technology that provides strain and temperature. Technical basic knowledge of these instruments is explained to understand the principle that is useful not only to follow but also to take advantage of the next generation of instrumentation becoming to prevail at present and in near future.
Instrumentation and Monitoring for Forensic Geotechnical Engineering
Developments in Geotechnical Engineering
Rao, V.V.S. (editor) / Sivakumar Babu, G.L. (editor) / Iwasaki, Y. (author)
2015-08-29
19 pages
Article/Chapter (Book)
Electronic Resource
English
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