Shallow Soil Mixing (SSM) is a sister technology to Deep Soil Mixing (DSM) developed to more economically improve soils within ten meters of the surface. SSM was recently utilized to provide a foundation for large effluent storage tanks as well as to contain foundation soils in the event of liquefaction from an earthquake.
Two large storage tanks were required to be built in a pulp mill. The only area available which suited the overall building program was land reclaimed from the Strait of Georgia by end dumping silt and fine sand out into water. The fill was not compacted enough to adequately support the tank and was subject to liquefaction.
The geotechnical engineers considered a number of ground improvement and foundation support options. SSM was selected to provide optimal tank support under both static and seismic loading in relation to its cost.
The project yielded successful results. The columns achieved the proper strength, the schedule was shortened, and the solution cost less. This was the first use ever of large diameter soil mixed columns for foundations.
Shallow Soil Mixing - a case history