Idealized subsurface profile * The presence of shallow groundwater and the need to dewater the excavation while not inducing settlement of adjacent improvements. * The presence of artesian conditions in sand layers below the excavation and potential for heave or blowout at the bottom of the excavation. * Penetration of the structural shoring wall below the bottom of excavation for structural stability and to limit deep seated movements. * Penetration of the perimeter cutoff wall as necessary to limit groundwater pumping rates and drawdown of groundwater levels outside of the excavation footprint. Selection of Shoring System Tieback anchors were utilized to laterally restrain the very stiff perimeter shoring walls and limit the deflections of the shoring system. The shoring deflection limits, specified by the City of San Jose, are strict and are imposed with the intent of limiting the movement of adjacent public and private improvements to magnitudes that are well below those that are likely to have any meaningful impact on these improvements. Static groundwater was encountered between 15.5-30 ft (5-9 m) below the ground surface. To excavate the soil and construct the basement levels while maintaining subgrade stability, the groundwater within the basement excavation footprint needed to be drawn down at least 3 ft (1 m) below the bottom of excavation, which corresponded to lowering the groundwater about 45 ft (14 m) below pre-existing levels. If the groundwater level outside the excavation was lowered by this amount, it was estimated that settlements on the order of 3 in (76 mm) would have occurred within 50 ft (15 m) of the shoring system. This could have potentially damaged adjacent utilities, sidewalks and streets, and was not considered acceptable. Furthermore, as previously noted, PPDTs performed during the geotechnical investigation indicated the DEEP FOUNDATIONS * JULY/AUG 2024 * 93