When excavation for construction or repair purposes is more than a few feet deep and the sides of the excavation cannot be cut on at a stable slope, excavation support is necessary. Support of Excavation (SOE) system components often have to be coordinated with both existing conditions and new construction and are sometimes incorporated into the permanent work. A variety of structural materials and systems are used for excavation support, including wood sheeting, soldier piles with lagging, sheet piles, soil nails, secant piles and tremie concrete.
The behavior of an excavation support system is a soil-structure interaction problem that is indeterminate, nonlinear, time-dependent and subject to uncertainty as to applied loading and soil resistance. Due to this and the variety of subsurface conditions and SOE and bracing systems available, there is no one-size-fits-all approach to excavation support problems. Instead, the methods used to analyze an SOE solution must be commensurate with the quality of available data and the risks associated with adverse performance.
Richard J. Driscoll, Consulting Engineer (RJDCE) provides an integrated, interdisciplinary approach to below-ground structures and urban construction that is especially well suited to excavation support problems. RJDCE’s in-house knowledge and experience include an in-depth understanding of structures, soil-structure interaction and geotechnical considerations, along with sensitivity to constructability and a proactive approach to risk management. Therefore, RJDCE can assist owners, design professionals, contractors and other project stakeholders select, specify, analyze and design SOE systems and manage the risk associated with the excavations and support systems. RJDCE can also prepare construction documents and working drawings for support of excavation systems, perform peer reviews, review submittals and advise abutters exposed to risk from adjacent excavations. In addition, RJDCE presents forensic experience investigating performance failures of SOE systems and associated claims of damage to adjacent properties.