SECTION 614 - GEOCELL SLOPE PROTECTION
614.01 Description This work shall consist of designing, furnishing and placing a
Geocell Slope Protection System, in reasonably close conformity with the lines and grades shown on the Plans, as specified herein, and as directed by the Resident. The Geocell Slope Protection System consists of subgrade preparation, non-woven erosion control geotextile, geocell material into which select infill material is placed, infill material, anchors, and 6-46 surface treatment. This work includes subgrade preparation and placing and compacting Granular Borrow to the subgrade elevation.
614.02 Submittals Submittals shall comply with MaineDOT Section 105-General
Scope of Work. All information shall be submitted to the Resident thirty (30) days prior to the Geocell Slope Protection System installation.
A.Product Data. Submit manufacturer’s product data.
B.Supplier Design. Submit manufacturer’s project-specific design recommendations or engineering design for cell size, stake anchor length and stake anchor spacing. The project specific design shall be prepared, checked, and sealed by a Professional Engineer licensed in the State of Maine.
C.Shop Drawings. Submit manufacturer’s Shop Drawings including section layout, direction of expansion, and anchor stake locations. The Shop Drawings shall be sealed by a Professional Engineer licensed in the State of Maine.
D.Samples. Submit manufacturer’s samples of geocell sections, anchors, and end caps.
E.Material Certification. Submit manufacturer certification of polyethylene used to make geocell material including percentage of carbon black, polyethylene density, and environmental stress crack resistance (ESCR).
614.03 Materials Materials for the Geocell Slope Protection System shall meet the
requirements of the following sections: 614.031 Geocell Sections The geocell sections shall be a polyethylene sheet strip assembly connected by a series of offset, full depth, ultrasonic welded seams aligned perpendicular to the longitudinal axis of the strips, which, when expanded, form walls of flexible 3-dimensional, cellular slope protection confinement system. The geocell material shall be manufactured by Presto Products Company, Appleton, Wisconsin, Webtec Geosynthetics, Charlotte, North Carolina, or an approved equal. Sections shall be in conformance with manufacturers design recommendations or engineering design for this project.
1.Geocell base material The geocell material shall be polyethylene stabilized with black carbon, with the following properties:
a.Density, ASTM D 1505: 58-60 pcf.
b.Environmental stress crack resistance (ESCR) ASTM D 1693: 30 00 hours.
c.Ultraviolet light stabilization: carbon black.
d.Carbon Black Content: 1.5 t o 2 percent by weight, through the addition of a carrier with a certified carbon black content.
e.Homogeneously distributed through material. 6-47
2.Geocell Strip Properties and Assembly
a.Perforated Strip/Geocell: i Strip sheet thickness, ASTM D 5199: 50 mil minus 5%, plus 10%. Determine thickness in the flat before surface disruption. ii Sheet thickness: 60 mil +/- 6 mil. iii Polyethylene Strips: Perforated with horizontal rows of 0.40 in diameter holes. iv Perforation Within Each Row: 0.65 to 0.75 in on center. v Horizontal Rows: staggered and separated 0.50 in relative to hole centers. vi Edge of strip nearest edge of perforation: 0.24 in minimum. vii Centerline of spot welds to nearest edge of perforation: 0.70 in minimum.
b.Assembly of Geocell sections: i Fabricated using strips of sheet polyethylene each with a length of 12 ft and a width equal to cell depth. ii Connect strips using full-depth, ultrasonic spot-welds align perpendicular to longitudinal axis of strip. iii Ultrasonic weld melt-pool width: 1.0 in maximum.
3.Geocell Properties
a.Individual Cells: Uniform in shape and size when expanded. Over- or under- expansion of uniform individual cells will be allowed on curved slopes.
b.Individual Cell Dimensions: i Length: 8.8 in +/- 10% ii Width: 10.2 in +/- 10% iii Nominal area 44.8 sq in +/- 1% iv Nominal depth: 4 in
4.Geocell Seam Strength Tests
a.The seams for geocell sections shall consist of 2 carbon-black stabilized strips welded together.
b.Short Term Seam Peel Strength Test:
i.Cell Seam Strength: Uniform over full depth of cell. ii. Minimum seam peel strength: 320 lbf for 4 in depth.
c.Long Term Seam Peel Strength Test: i Conditions: Minimum of 168 hours (7 days) in a temperature-controlled environment that undergoes change on a 1-hour cycle from room temperature to 130º F. ii Room temperature: ASTM E 41. iii Test Samples: Weld two 4 in wide strips together. iv Test: Test sample consisting of 2 carbon black stabilized strips shall support a 160 lb load for the test period. 6-48 614.032 Anchoring Components The anchoring system shall consist of straight No. 4 steel reinforcing rods with an ATRA clip, or an approved equal, as end cap. Length shall be as specified in the manufacturer’s recommendations or the project-specific design. 614.033 Granular Borrow Granular Borrow shall meet the requirements of MaineDOT Section 703.19 - Granular Borrow, Material for Embankment Construction. 614.034 Geocell Infill Material Geocell infill material shall be as specified in the project-specific design or as shown on the Plans and shall meet the requirements of the following specifications: L o a m 615.07 D i r t y B o r r o w 615.10 Aggregate for Crushed Stone Surface 703.12 614.035 Surface Treatment For geocell slopes with Loam infill, the surface treatment shall consist of seed and an erosion control blanket. The seed shall meet the requirements MaineDOT Section 618-Seeding, Method Number 2, or as indicated on the project-specific design, Plans and Notes. The erosion control blanket shall meet the requirements of MaineDOT Section 613-Erosion Control Blanket. When infill other than loam is specified, the surface treatment shall be as indicated on the project-specific design, Plans or details.
614.04 Construction Requirements The Geocell Slope Protection System shall have the
following construction requirements:
A.Subgrade Preparation.
1.Prepare the subgrade by removing the all existing vegetation and loose surficial soils from the slope.
2.Excavate and the slope section as needed.
3.Place, compact, and shape Granular Borrow as needed, so that when placed the top of installed geocell section is flush with or slightly lower that the final grade as indicated on the Plans.
4.Install non-woven erosion control geotextile underlayer, if required, on the prepared surface, ensuring required overlaps are maintained and outer edge of geotextile are buried a minimum of 6 in. below grade.
B.Placement and Anchoring.
1.Anchor geocell sections at the crest of the slope or as per manufacturer’s recommendations. Use type of anchor and frequency of anchoring as indicated on the shop drawings.
2.Expand geocell sections down slope. Confirm each geocell section is expanded uniformly to required dimensions and outer cells of each layer are correctly aligned.
3.Interleaf edges of adjacent sections. Ensure that the upper surface of adjoining geocell sections are flush at the joint and adjoining cells are fully anchored. Anchor with specified anchors in prescribed pattern throughout the slope surface. 6-49
C.Placement of Infill.
1.Place infill in expanded cells with suitable material handling equipment, such as a backhoe, front-end loader, conveyor, or crane mounted skip. Limit drop height to a maximum of 3 ft. Avoid displacement of the geocell sections by infilling from crest to toe of slope.
2.Overfill and compact infill in accordance with consistency of material and cell depth as follows: a For geocell slopes with loam infill, overfill the geocell with 1 to 2 in loam and lightly tamp or roll to leave soil flush with top edge of cell walls. b For geocell slopes with Aggregate for Crushed Stone Surface or Dirty Borrow infill, overfill the cells approximately 1 inch and compact with a plate tamper or backhoe bucket. Remove loose surface material so infill is flush with top edges of cells.
3.Apply specified surface treat ment as specified in project-specific design or on the Plans.
614.05 Delivery, Storage, and Handling
A.Delivery. Deliver material to site in manufacturer’s original unopened containers and packaging, with labels clearly identifying product name and manufacture.
B.Storage. Store materials in accordance with the manufacturer’s instructions. Store material out of direct sunlight.
C.Handling. Protect materials during handling and installation to prevent damage.
614.06 Method of Measurement The Geocell Slope Protection System measurement
will be by the square foot of material installed.
614.07 Basis of Payment The Geocell Slope Protection System will be paid for at the
Contract unit price per square foot which shall be full compensation for design, all labor and materials, including non-woven erosion control geotextile, the geocell material, anchoring components, granular borrow, infill, and surface treatments. The unit price shall be full compensation for subgrade preparation, and placing and compacting Granular Borrow to the subgrade. P a y I t e m P a y U n i t
614.30 Geocell Slope Protection System Square Foot
Referenced in this section
Sections that cite this one
Get an email when 614 changes
Maine revises spec sections through supplementals and new editions. We check this one every week and email you the day it changes. Free, no account.
Source: Standard Specifications — Highways and Bridges, 2020 Edition. Pages 515–519 of 817. View official source ↗