Ground Stabilization in the Sacramento Railyards: DSM Columns and Secant Piles
As part of the Sacramento Railyards project, Malcolm, in collaboration with Brierley Associates, designed and constructed a stormwater outfall structure. To mitigate liquefaction risks and provide a bottom seal, Malcolm installed 5.5-foot and 9-foot diameter Deep Soil Mixing (DSM) columns beneath the entire sump structure. The soil profile consisted of clayey sand in the upper 10 feet, underlain by clean sands, silty sands, and silts — all alluvial deposits from the Sacramento River.
Malcolm also installed 3-foot diameter secant piles around the sump structure for excavation support and as a permanent wall for the sump structure, using the CFA pile method.
Located adjacent to the Sacramento River levee, the project encountered challenges during heavy rain events that caused the river’s level to rise by 9 feet. This, in turn, elevated the groundwater level to the construction grade, partially delaying operations.
Rigorous quality control measures were implemented, including extensive grout testing to verify unconfined strength, vertical continuity of the DSM columns, and proper overlap between adjacent DSM columns and CFA piles.
