Winamac Solar Farm

As construction began on the haul roads to build the solar farm, the contractor encountered very soft soils and struggled to get equipment on site to cut haul roads to grade. The subgrade material consisted of Silty Sand (SM) with 12% clay particles and 6% silt. Even at relatively small percentages, clay and silt can have an outsized effect on the sensitivity of a soil to construction traffic and changes in moisture content. The soil content and the imperfect drainage characteristic of agriculture land quickly created a situation where haul roads and laydown areas became unmanageable. The contractor’s initial plan was an expensive 30” undercut and the use BX1200 to stabilize the subgrade.

The contractor called Tensar to see if using advanced InterAx geogrid could reduce the undercut. Tensar and local distributor Ferguson visited the site the same week to perform DCP testing at the site and calculate the the subgrade CBR. Tensar+ design software provided a solution that reduced the undercut to 15” using InterAx NX850 geogrid. This saved the project on stone costs, construction time and lowered the overall carbon impact.