Deep Soil-Mixed Permanently Tied-Back Retaining Walls
Lake Parkway - St Francis (Railroad) Tunnel
E. Elizabeth Avenue To E. Fernwood Avenue
Milwaukee County, Wisconsin

This project involved the design and construction of permanently tied-back (anchored) retaining walls using in-situ Deep Soil Mixing (DSM). The combined retaining walls were 5,800 feet in length with depths that ranged from 30 to 60 feet. Steel soldier piles were placed within the freshly mixed soil-cement-bentonite mixture on 4.5 foot centers. This was done while the mixture was still fluid.

The DSM walls were designed to have an unconfined compressive strength of 75 psi in 28 days, with a maximum allowable groundwater leakage of 500 gallons per day lineal foot of wall. The DSM walls were constructed in an urban neighborhood. Over 75% of the wall length was adjacent to an active railroad track. The DSM walls intersected two railroad crossings which were removed and restored within a 24-hour period. Equipment used in constructing the DSM walls included a DSM rig mounted on a 150 ton crane, 5,000 lb. vibratory hammer mounted on a 100 ton crane, slurry batch plant, and other earth moving equipment.

• Start: 2/15/97
• Completion: 8/30/97