APPLICATION: Rex Energy, the project owner, used the Spectra® Subgrade Improvement System, a mechanically stabilized layer incorporating TriAx® Geogrid, to create unyielding platforms at two locations. The first location (Bame) needed a drill site and a 1,000-foot access road. The second location (Warner) required a drill site and a 2,500-foot access road.
THE CHALLENGE: Rex Energy is an independent energy company engaged in the acquisition, production, exploration, and development of oil, natural gas, and natural gas liquids with a majority working interest in multiple natural gas exploration projects in Butler County, Pa. The Bame and Warner sites are farmland where there is no provision for heavy-equipment access.
SITE CONDITIONS: Most of the soils on the Warner site needed moderate improvement, but the subgrade at the site entrance was quite soft. At the Bame pad, a high water table contributed to very soft soil conditions throughout the site.
ALTERNATIVE SOLUTIONS: Kozik Construction, the owner’s general contractor, typically used one to two feet of crusher run over geotextile to stabilize project sites. But aggregate costs are increasing throughout the region, making this approach increasingly expensive.
THE SOLUTION: Tensar International Corporation regional manager David Lipomi advised using the Spectra System with a combination of TriAx TX190L Geogrid and TriAx TX160 Geogrid.
Designed for the demanding loads of the rail industry, TX190L Geogrid offers an aperture that is ideal for bridging saturated and crumbling soils with less expensive 3-inch-minus stone. TX160 Geogrid has a smaller aperture that works well with a well-graded aggregate with a top size of 1.5 inches.
“TriAx Geogrid has a high-rib profile and a unique hexagonal shape that gives 360-degree load distribution,” says Lipomi. “Our deep product line shows how we can address tough site conditions while still using less aggregate than more traditional stabilization methods.”
Lipomi specified TriAx TX190L Geogrid for the Bame site’s well pad and 1,000 linear feet of access road. To install the project, Kozik’s crew leveled the sites so they could lay the geogrid flat and level.