The Use of Geotechnical Instrumentation and CPTu for Investigation of Geotechnical Failures During Construction in Civil Engineering Projects

Abstract

It is important to do monitoring of works during construction of Civil Engineering Projects due to many aspects including for safety purposes and information on the performance of the on going activities. Many engineers have done so, however they have used them only as data reporting without providing any interpretation and understanding, hence the reports are meaningless; no further use on the collected data except when failures occur and it is too late to provide necessary action. In many cases, these data provide feedback for design and analysis assumption where designers may assess the performance of his own design, giving a chance to review and revise the dimensions or even to save when overdesigning or to strengthen if the design is critical. Based on these data, back analysis can be conducted to confirm the design. The geotechnical instrumentations have been used to measure pore water pressures (piezometers), surface settlement (settlement plate), subsurface settlement (extensometers), subsurface horizontal movement (inclinometers), inclinations of structures (tiltmeters), soil pressures (stress cell) etc. This paper represents experience of the authors’ works throughout many years of geotechnical projects on the use of the geotechnical instrumentation such as the case of slope failures and landslides, excavation, heave and excess pore pressures due to pile driving, bridge monitoring in landslides area, reclamation works etc. The first case history is on failures of sheetpiles on Soft Soils and the second case is on the damage of buildings due to mass driven piling works. Many lessons learned from these observations using instrumentation and many data were obtained to prove the assumptions or new findings enhancing the theory, but most important is the generated excess pore pressure monitored by the geotechnical instrumentations may reveal the cause of failures and most important role of geotechnical instrumentation to serve for the public safety.