City: Cleveland

State: OH

Owner: University Hospital of Cleveland

General Contractor: Martin Enterprises

Project Description:

Jet grout columns were used to create a water cutoff wall for an excavation in water bearing silty sands beneath an existing hospital building.  The building was supported on drilled piers bearing on shale bedrock.  The original excavation support design included drilled soldier beams with tiebacks and wood lagging.  This design was based on complete dewatering of the silty sands.  However, dewatering did not occur, making the installation of wood lagging nearly impossible.

Jet grouting was chosen to substitute for wood laging in the wet silty sands.  A jet grout test program was conducted before production to determine the optimum grouting parameters.  Once the parameters were chosen, a total of 40 overlapping jet grout columns were installed between the soldier beams and also between the soldier beams and drilled piers.  The jet grout columns were located to ensure good overlaps and create a watertight seal.

The jet grouting performed well.  During excavation, the jet grout columns were trimmed to the face of the soldier beams using an excavator with a flat blade.  No water inflows were encountered and most importantly, no loss of ground was experienced under the hospital building.