When exploiting oil, gas, mineral, timber, or other natural resources, it is often necessary to move heavy equipment long distances through wilderness or other undeveloped terrain which lacks permanent roadways. In addition to the lack of roadways, such undeveloped terrain often includes wetlands, muskeg, water bodies, or other unstable terrain which may result in heavy equipment sinking, losing traction, or being otherwise delayed. A variety of solutions have been provided, including temporary or permanent bridges, swamp mats, rig mats, and access mats.
Previous systems necessarily balanced between ability to carry the required loads, durability, cost and ease of installation. The required loads and durability define requirements of the previous systems. The cost and ease of installation of any such system would be constrained and determined by the required load and required durability. Durability may be particularly important where the road or bridge is intended to remain in place during inhospitable portions of the year in climates which experience extreme temperatures, humidity, or other factors which result in increased wear. In addition, any solution for providing access to remote locations will often traverse fragile ecosystems which are subject to local regulation, public pressure, or both.
Muskeg or similar wetlands may be difficult to use as a subgrade in road construction. When a road is built over such terrain, road failure may result from lateral flow (shear) or compression (excessive settlement). Failure due to lateral flow may occur when the subsurface is pushed out from underneath the road as a result of gravitational force of the road on the subsurface, resulting in the road subsiding into the subsurface which remains under the road.
USPTO Backgrounds
USPTO Backgrounds