DATE: 9 July 2007
CLIENT: The Trenchless Company, Sacramento, CA
JOB LOCATION: Agilent Technologies, Santa Clara, CA
JOB: 200' sewer section replacement under parking lot divider planted with mature
redwood trees, replacing 8quot; VCP line with 8quot; SDR7 PE, pulling upstream
Product testing new 8quot; Footage/TRIC Unified Force impactor head
TOOLS: WC22 hydraulic ram, Case 580 back hoe
530 Stevens Creek Boulevard, Santa Clara, CA
Sewer runs under lot/lane divider planted with mature trees.
Fusion and landing area on lot side.
View from entry end (downstream excavation).
Entry pit is 0 to 2 feet deep with shoring. Existing clay pipe is bedded in sand. Sewer was lined from this point to lower manhole 20-30 feet
downstream in order to avoid excavation or bursting around large water main crossing sewer path.
Using jetter to retrieve and pull back 220’ of air hose.
Attaching air hose to jetter hose.
Feeding back air hose from head end.
Air hose arrives at tail end.
Impactor attaches to hose and then slides into sealed bursting head.
Drilling and securing pipe to head with set screws.
Attached to standard clevis and ready to test.
WC22 ram set on pulley base in exit pit, ready to insert cable.
Puller is removed when cable clevis approaches pulley wheel, then cable is detached and replaced with a chain to hook to backhoe bucket.
Shoring/excavation is perpendicular to pipeline, so space is limited for bucket to pull with hammer assist.
Directing force in line with pipe in deep, confined space is difficult.
Pulling another two feet or so, with impactor.
When head is pulled as far as space allows, backhoe is moved to entry pit for attempted push.
Cutting pipe in entry pit, being careful not to cut air hose.
Pushing with hammer makes little or no progress.
Head assembly is moved to compressor to attempt removal of impactor.
Hooking impactor up to air supply after setting hammer in reverse.
Impactor is firmly wedged inside head.
Still no separation. Applying anti-seize on impactor shaft prior to use might facilitate removal after job, or perhaps standing the unit on its nose
against a solid surface would help the hammer release itself. Otherwise, modification of mating surface inside mole may be in order.