8″ Toe Drain Abandonment

Montgomery Village, Maryland

The Job

Lake Whetstone is an approximately 30 acre manmade impoundment located in Montgomery Village, Maryland. It is utilized for stormwater runoff control, and also recreation, with an approximately 1000LF earthen dam.

As part of a retrofit program of the embankment, two 8″, perforated CMP toe drain pipes needed to be grouted for a minimum of 100LF, under active flow.

The Challenge

Each of the two, 100′ long pipes needed to be grouted full, but could only be access from the downstream end of the pipes. One pipe had nominal flow, and the second pipe had approximately 10GPM, and discharged 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 “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.

CJGeo performed the onsite mockup testing and analysis, and then grouted the two pipes in place successfully over a period of two days onsite.

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