SFPUC SE Water Pollution Control Plant: T31.01 (CMGC)

This CMGC project was awarded as part of the SFPUC’s Southeast Water Pollution Control Plant Biosolids Digester Facilities Project (BDFP).

The project consisted of 1200 LF of reinforced diaphragm slurry cutoff walls; 1260 LF of Cement Cutter Soil Mixed (CSM) cutoff walls with 180 each W30 soldier pile, 232 each 4-foot diameter drilled shafts (CIDH Pile) at 87 feet deep, 135 each 4-foot diameter auger cast piles (CFA) at 65 feet deep; 267 each 3-foot diameter auger cast piles at 65 feet deep; 623 each post-tensioned shoring wall tiebacks, 521 each 1-foot diameter micropile at 60 feet deep; internal bracing for several structures; 105,000 CY of excavation of multiple structures up to 40 feet below existing grade and 30 feet below existing water table; hauling and disposal of 155,000 tons of excavated soils, including management and disposal of federally regulated contaminated soils; complete dewatering system including treatment system and regulatory permitting; and site restoration, structural concrete, embankment, grading, and paving.

The reinforced diaphragm cutoff wall is 3 feet wide and up to 167 feet deep, placed in 76 individual sections, and excavation utilized bentonite slurry that was mixed and processed on site. The diaphragm cutoff wall serves as both a cutoff wall and an integrated shoring system to facilitate excavation.