OUTER HARBOR
Buffalo, New York
Remedial Construction Services, L.P. (RECON) was contracted by Honeywell International to use its soil mixing and jet grouting technologies to assist with the remedial action and redevelopment of the Outer Harbor in Buffalo, New York.
Phase I, Soil Mixing
The initial phase of the project included the in-situ chemical oxidation to stabilize the nitrobenzene-impacted soil. RECON installed 155 columns using the Single Auger Mixing (SAM) technique. The 8-foot diameter columns were overlapped to ensure the entire 5,400 cubic yards of impacted soil was treated. Oxidizing agent (Potassium Permanganate) was introduced at a rate of approximately 600 pounds per column and was mixed with the impacted soil between 8.0 and 22.0 feet below ground surface for 20 minutes.
RECON used its own RH190 Delmag crawler-mounted hydraulic drill rig to advance, rotate, and withdraw the mixing tool. The drill rig has a top drive rotary head capable of transferring 190,000 foot-pounds of torque to the mixing tool. The RH190 is capable of producing a crown force of 73,000 pounds and an extraction force of 92,000 pounds. It is equipped with a cab-mounted, real-time monitoring system that allows the driller to control the soil mixing operation by monitoring the tool rotation speed, tool penetration, and agent/grout placement.
Phase 2, Jet Grouting
Phase 2 included injecting additional Potassium Permanganate to treat "hot spot" areas identified after verification sampling. RECON used our jet groutin rig to deliver the reagent because the chemically oxidized area was impassible, and the jet grouting rig provided angular drilling.
RECON's jet grouting rig includes a hydraulic drill equipped with the capability of injecting reagent. This procedure influenced a 1-foot diameter zone around the drill stem. RECON's high-pressure pump delivered reagent at a rate of 40 gpm at a pressure of over 6,500 psi. The jet grout pump delivered the reagent solution from an agitated holding tank through a hose to a swivel on top of the mixing tool shaft. The swivel allows the reagent mix to flow through the shaft and exit through ports on the mixing tool while the tool is rotating. The flow rate was modified at the pump with a flow meter to ensure placement of the prescribed reagent dose.
Phase 3, Soil Stabilization and Final Treatment
Toxicity Characteristics Leaching Procedure (TCLP) levels of nitrobenzene were lowered to a maximum of 35.4 ppm as a result of Phase 1 and 2 treatment events. Treatability studies were performed by RECON to determine the percentage of cement required to stabilize the remaining fluidized material. Additionally, it was decided to mix 4% granular activated carbon (GAC) to absorb the majority of the remaining nitrobenzene. Adding the GAC reduced the nitrobenzene levels by 98%.
After the treatability studies were presented to, and accepted by, the agencies, RECON re-mobilized the Delmag soil mixing rig to perform cement-GAC stabilization of the fluidized area as the final treatment.
This project used jet grouting to construct insitu mixed columns of soil and grout to accomplish the following tasks in support of a microtunneling operation:
Sims Bayou is a major stormwater conveyance feature that comes under the auspices of the U.S. Army Corps of Engineers (USACE). When a deep failure plane -- caused by the presence of low-strength soils combined with a seasonal upward hydraulic gradient -- developed along a stretch of the bayou’s 20-foot high embankment, the USACE selected the single-fluid jet grouting technique to stabilize the slope.