222GEOCELL LOAD DISTRIBUTION MAT

222.1DESCRIPTION—This work is the construction of a geocell load distribution mat over soft or unstable

subgrades.

222.2MATERIAL—

uniformly extended position until backfilling of geocell is complete. Provide anchors in accordance with the manufacturer’s recommendations and as indicated, except having a minimum bar diameter of 0.375 inches and a minimum length of 12 inches plus the geocell depth.

in accordance with the manufacturer’s recommendations and capable of holding adjacent geocell panels in direct contact until pavement or other type of final surface is placed.

222.3CONSTRUCTION—Install the geocell according to manufacturer’s instructions and as follows:

grade indicated.

adjacent layers and extend a minimum of 6 inches beyond the indicated perimeter of the installed geocell.

Position collapsed geocell sections in place and drive in the anchors starting at the outer edge cells. Drive anchors as required by the manufacturer or as required to fully expand a geocell panel to the required cell dimensions and to hold it in place until filling with subbase is complete. Drive anchors so that the anchor extends at least 12 inches below the bottom of the geocell. Allow enough anchor length above the top of the geocell for the anchor to be removed. Remove anchors after filling the cel ls with subbase and before compaction when used for subgrade support and pavement applications. In situations where it is not practical to use anchors (i.e. over soft soil containing obstructions to driving anchors, existing shallow utilities, etc.) an ins tallation frame may be needed to allow for the expansion of the geocells without anchoring in place. The installation frame must be capable of fully expanding the geocells and holding them in place until the subbase is placed in the cells. Align adjoining geocell sections and overlap abutting perimeter cell welded ends. Keep top of geocell sections flush before fastening. Connect adjacent geocell sections with mechanical fasteners, in accordance with the manufacturer’s recommendations. M echanical fasteners must be capable of holding adjacent geocell panels in direct contact until pavement is placed. Fasten all adjoining cells of adjacent geocell sections and all overlapped abutting perimeter cell welded ends. Place subbase in cells of expanded geocell sections. Overfill cells sufficiently to ensure the top of the compacted subbase is at least 1 inch above the top of the geocell to allow fine grading as necessary or required and to protect the geocell from construction traffic and heat during paving operations . Limit the

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drop height of the subbase to a maximum of 3 feet to prevent damaging or displacing the cell wall. Do not operate equipment on unfilled geocell sections until cells have been overfilled with loose subbase. Compact subbase as specified in Section 350, except when cells greater than 6 inches in height are used. When cell height exceeds 6 inches, compact as specified Section 350, except allow compacted lift thickness 1 to 2 inches greater than the cell height.

222.4MEASUREMENT AND PAYMENT—

Includes mechanical fasteners and anchors.