A Case Study: Unreinforced Soil Mixing for Excavation Support and Bearing Capacity Improvement

Soil mixing is widely used for environmental site remediation and ground improvement. The main objectives of soil mixing are to increase the strength and decrease the permeability of the soils. Conventionally, unreinforced soil mixing is an uncommon choice for an excavation support system, but a recent case study highlights the potential advantages of using a single technology to accomplish multiple site objectives. The case study provides an overview of the site history, of the design methodology, and of the installation methods used in Lexington, VA. The work was performed in April and May of 2010. Wet “grab” soil-grout samples were collected immediately following installation. All of the soil-grout quality control samples achieved the project design minimum of 100 lbs/in 2 (~690 kPa) in less than 28 days of curing.