A substantial milestone was reached in the recovery shaft repair process on Tuesday, Sept. 12 when contractors began pumping cellular grout into the shaft to encase the HOBAS pipe. Once this is finished, the remainder of the shaft will be back-filled with sand, and the steel girders will be removed as the back-filling is completed.
The 9-ft. 2-inch diameter HOBAS pipe lining is in place in both the 3,700 feet of the 11 ft. diameter interceptor to the east of the former sinkhole, and also in the 300 ft. recovery shaft which is where the former sinkhole was located, the HOBAS pipe has been secured to the reinforced concrete floor of the shaft, and cellular grout is being pumped into the shaft.
When the HOBAS is secured in place and covered by the grout, back-filling of the recovery shaft, measuring 300 ft. long, 26 ft. wide, and approximately 60 ft. deep, and the pre-cut that surrounds the shaft which is approximately another 10 ft. deep, can begin. It’s estimated that it will require 30,000 cubic yards of fill to complete the back-fill.
Demobilization of the miles of bypass piping, the bypass and dewatering wells and pumps can begin soon after the sewage flow is once-again directed through the newly repaired interceptor piping. Remediation and repair of roadways, especially 15 Mile Road and the Eberlein entrance, drives, easements, parking lots, etc. will also begin in the near future.
The bottom of the 300 ft. long recovery shaft, looking east with the 11 ft. diameter pipe at
the end of the shaft.
The “Batmobile” highly specialized pipe carrier being lowered into the recovery shaft to install the HOBAS pipe that lines the old 11 ft. interceptor pipe and is also used in the recovery shaft.
The “Batmobile” and workers preparing to insert a 20 ft. section of HOBAS pipe 70 ft. below ground level.
The HOBAS is being installed in the recovery shaft from both the east and west ends of the shaft, and very near completion in this photo.
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