Design Guide for Community Water Systems - The Water, Sanitation ...

e circulated in the annular space sufficient to clearobstructions.4. When grouting a well, one of the following methods shallbe used:1. The Positive-Placement Interior Method: When theannular opening is less than three inches (the diameterof the drill hole is less than six inches larger than thecasing diameter), grout shall be installed using thepositive-placement interior method. This methodinvolves introducing the grout through the well casingor a pipe inside the well casing. Either an expandable ordrillable plug shall be installed at the bottom of the wellcasing and the grout pipe shall extend through this plug.Then grout shall be installed under pressure by meansof a grout pump from the bottom of the annular openingupward in one continuous operation until the annularopening is filled. If the grout does not reach thesurface, the driller shall wait at least 24 hours and thendetermine the elevation of the top of the grout. Theappropriate Department of Natural Resources RegionalOffice shall be contacted for approval of the methodused to complete grouting of the well by using thetremie method;2. The Positive-Placement Exterior Method: When theannular opening is three or more inches (the diameter ofthe drill hole is six inches or more larger than the casingdiameter) and less than 300 feet in depth, grout may beplaced by the positive-placement exterior method. Thismethod requires pumping grout through a grout pipeinstalled in the annular opening. The maximumdiameter of the grout pipe shall be at least 1½-inchessmaller than the annular opening. The grout shall beplaced to the bottom of the annular opening in onecontinuous operation until the annular opening is filled.The grout pipe shall be raised as the grout is placed butthe discharge end of the grout pipe must be submergedin the placement grout at all times until grouting iscomplete. The grout pipe shall be maintained full, to thesurface, at all times until grouting is complete. In caseof interruption of grouting operations, the grout pipemust be removed from the drill hole and all air andwater displaced from the grout pipe and the pipeflushed clean with clear water. After the grout pipe iscleaned, it may be placed in the drill hole and groutingresumed; or3. The Tremie Method: When the annular opening is fourAug. 29, 2003Page 39