30 Sep 01
To ensure the as-built cover meets the performance objectives.
To verify that geosynthetics are not damaged during construction.
To conduct large-scale permeability tests using sealed double ring infiltrometers.
To determine material placement criteria.
(2) Design Criteria. Test fills are often constructed on the steepest slope of the landfill cover,
which provides a worst-case scenario for slope stability and placement techniques. A test fill should be
a minimum of three times the width of the compaction vehicles. Widths are typically 1015 m (3050
ft). Lengths should be sufficient to allow equipment to reach proper operating speed for a minimum of 8
m (25 ft). Test fills are typically 2030 m (65100 ft) long. The materials, construction procedures,
and test procedures should be as specified for full-scale construction of the landfill cover. Before
beginning construction, the contractor should be required to construct drainage controls to divert surface
runoff around the test fill. Guide Specification 02318 should be used as part of the contract documents
for the test fill design.
(a) Testing. Density, moisture content, classification, and permeability tests should be
performed on each lift of the test fill clay layer. Shelby tube samples collected for permeability testing
should also be examined to determine if there has been good interface bonding between lifts of clay.
Geomembrane seams can be destructively tested for strength and non-destructively tested for leaks.
Seams for geotextiles and geogrids should be tested if they will be required to carry tensile loads. Tests
should be required on other components of the test fill, as needed, using test procedures outlined in the
construction specifications. Survey control points are often placed along the sides of the test fill and
consist of pins set back from both sides of the edge of the test fill at approximately 6-m (20-ft) intervals.
Markings are placed on the outside edges of the geosynthetics in the test fill so that the relative
movement between the geosynthetics can be monitored. Control points are typically surveyed
immediately after construction and every 5 days thereafter for the life of the test fill. After the test fill is
built, a 6- by 6-m (20- by 20-ft) section should be carefully dismantled to inspect for damage to the
(b) Work Plan. The contractor should be required to submit a detailed work plan describing
all aspects of the proposed test fill section construction and monitoring. This plan should include scale
drawings, survey procedures, test procedures, and equipment to be used. The contractor should also
submit a post-construction report that includes as-built drawings, test results, survey data, and
conclusions. The contractor should be required to videotape construction and dismantling of the test fill.
d. Borrow Areas.