All schematics are preliminary except as noted.
Left untreated, North Texas' notorious shifting clay soil can wreak havoc on multimillion-dollar, multiton structures such as the President George Bush Turnpike. So the North Texas Tollway Authority is taking extensive and expensive steps to make sure the road and the dirt under it don't move. On most road projects, crews treat soil with powdered lime to prevent it from expanding and contracting as the moisture content changes. The cure would be worse than the ailment. Gypsum, a component of sheetrock, would react with the lime in cold, moist conditions and cause the soil to shift.