Low Level Outfall Abandonment
The Job
This low level outfall abandonment grouting project is located in New Jersey. The Round Valley Reservoir, in Clinton Township, New Jersey is a 2300 acre man-made drinking water reservoir. It serves extensive portions of New Jersey. It was constructed by damming up two openings in a naturally-curved mountain.
As part of a dam upgrade project, a 1400LF, 36″ inner diameter LLO pipe needed to be grouted to place it out of service.
The Challenge
The pipe had been previously blind flanged, 180′ below the lake surface. There was a single, 12″ riser pedestal. There were numerous significant challenges to face, including:
- 2GPM residual leak from the blind flange buried in 15′ of lake floor debris
- inability to push sacrificial pipes more than 500′ up the pipe
- remote site with limited ready mix service
The Solution
CJGeo worked with the general contractor, diving subcontractor, sacrificial grout pipe installation subcontractor, geotechnical and civil EORs, and the owner, to develop a single stage grouting plan to place approximately 350CY of 68lb/cuft CJFill-Under Water cellular grout from the downstream end.
Venting was achieved by installing a 4″ removable vent pipe from the pedestal riser. The vent pipe ran 180VF to the lake surface, terminating on a barge. There was only one opportunity to do the job correctly. Therefore, CJGeo had two fully staffed grout plants onsite, and had all cement and mix water staged in onsite storage. This was all prior to the start of grouting to avoid any material logistics disruptions affecting the work.
CJGeo placed the 68lb/cuft grout over a period of a few hours, leaving an intentional air pocket at the high end to capture infiltrating lake water long enough for the grout to set prior to seeing lake head.
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Facing a similar challenge to this low level outfall abandonment project? Give us a shout or shoot us a text. Click the state marker for the location of your project for contact info for the appropriate rep.
DeRuyter Reservoir Outfall Abandonment
The Job
This outfall abandonment project is located in Upstate New York. The DeRuyter Reservoir, in DeRuyter, New York, is a 557 reservoir that’s originally part of the Erie Canal system.
As part of a dam upgrade project, the three parallel 22″ diameter, 300LF outfall pipes were to be abandoned. Along with a stone box culvert downstream of the valve chamber the pipes terminated into.
The Challenge
Each of the three pipes had been previously blindly flanged by divers. Therefore, the only access was from the downstream end within the valve chamber. In order to vent the air displaced by the abandonment grout, vent or placement points needed to be installed just behind the upstream blind flanges. The blind flanges are approximately 40′ below the water surface.
The Solution
CJGeo worked with the general contractor to design an internal venting system utilizing sacrificial placement pipes installed from the valve chamber. After each of the sacrificial grout pipes was installed, the downstream terminations were bulkheaded, with vent stubs.
CJGeo mobilized a cellular grouting crew, who placed 30lb/cuft CJFill-Ultra Lightweight cellular concrete through each of the sacrificial grout pipes, until grout returned to the bulkhead vents, confirming fill. The work took two days. The first day for the abandonment pipes and first lift in the box culvert, and the second day for a top-off pour on the box culvert.
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Facing a similar challenge to this outfall abandonment project? Give us a shout or shoot us a text. Click the state marker for the location of your project for contact info for the appropriate rep.
Toe Drain Abandonment
The Job
This toe drain abandonment project is located outside of Washington, DC. Lake Whetstone is an approximately 30-acre manmade impoundment located in Montgomery County, Maryland. The approximately 1000LF earthen dam provides stormwater runoff control and recreation.
As part of a retrofit program of the embankment, two 8″, perforated CMP toe drain pipes need to be grouted for a minimum of 100LF, under active flow.
The Challenge
Each of the two, 100′ long pipes needed to be grout filled. The pipes are only could only be accessable from the downstream end of the pipes. One pipe had nominal flow, and the second pipe had approximately 10GPM of flow. Each discharges through an end wall structure at the stilling basin.
The Solution
The project designer, Gannett Fleming, specified NSF Section 61 certified grout (potable water contact) for the abandonment grout. Due to the “one-shot” nature of the project, above-ground mockups, including sacrificial pipe installation, chemical grout cup testing, yield analysis, and visual inspection, were all required prior to the start of grouting.
While most abandonment grouting uses high mobility cement grout, like CJFill-Ultra Lightweight, chemical grout was the best option for this abandonment. Chemical grout’s reaction speed (and therefore mobility) is controllable onsite by variable catalyst dosing. This helps ensure minimizing any migration of grout into adjacent structures or waterways.
CJGeo performed the onsite mockup testing and analysis, and then grouted the two pipes in place successfully over a period of two days onsite.
Speak With An Expert
Facing a similar challenge to this toe drain abandonment project? Give us a shout or shoot us a text. Click the state marker for the location of your project for contact info for the appropriate rep.
