Image courtesy of Sundt Construction 3_D model section view of a plan for a trench to bury a sewer line 45 ft below grade. VDC analyzed scenario calls for a two step process to excavate a trench wide enough to hold the spoil from a second trench dug in the center to minimize hauling while maintaining safe slopes and achieving the depth required. Related Links: Read Cylwik and Dwyer's full paper: Virtual Design and Construction in Horizontal Infrastructure Projects Construction processes in vertical buildings are often repeatable—and repeated. That helps make that kind of construction a good fit for building