Abstract:
Construction in Miami Florida has exploded in the last 10 years. Due to the high water tables and infinite depths of high permeability soils and rock, traditional building structures within this geography tended to have the lowest levels at or near grade. Parking and mechanical equipment to service these buildings repeatedly occupied the first several floors of the structure. However, the movement for sustainable development, lead by the local communities and legislation, has pushed developers, engineers, and architects to think of creative ways to create more dynamic, usable, and communal space at the street level. One such solution involved pushing the parking and mechanical space below ground and then using the street level space for retail, commercial, and community focused purposes. Design and construction challenges arose due to the geological conditions and high water table. The presentation will focus a several marquis projects in the south Florida area that involved deep excavations in conditions where the water was at or near the ground surface and the soils consisted of material with permeabilities so high or the excavations were so large that pumping was not feasible. The presentation will focus on the use of deep soil mixing (DSM) for excavation support systems and the cutoff of lateral water flow. It will also focus on the use of an innovative secant DSM base plug system that restricted upward vertical flow into deep excavations and excavations that extended over multi city blocks. The presentation will focus on the design and construction considerations and challenges encountered during the projects, the performance of the DSM SOE and base plugs during the excavation and construction stages of the work, and the quality control measures used to validate the design and construction considerations.