Ventura 01 Slope Restoration

In 2021, Caltrans hired Flatiron-Drill Tech (FDT) to construct permanent support structures along two eroded sections of Southern California’s Pacific Coast Highway. FDT demonstrated that Drill Tech’s custom fleet could install ground anchors by reaching over the walls, which meant Caltrans could greatly reduce the diameter and depth of the planned secant piles and save costs. Caltrans and FDT hired Group Delta to perform a subsurface investigation to further minimize the project size; the combined plan changes saved the project tens of millions of dollars and allowed for two-lane traffic to flow throughout the duration of the project, pleasing Caltrans as well as local businesses and communities. Apex Rockfall Mitigation, another Drill Tech subsidiary, installed rockfall netting to protect the temporary traffic lanes.

The primary secant piles were constructed in segments dependent on bedrock depth and backfilled with corrosive environment concrete to protect from future tidal surges. Complex ground conditions and heavy rain complicated construction at the second worksite, so FDT deepened the wall’s primary piles and supplied additional support beams, providing extra slope support during casing extraction. FDT drilled and reinforced the secondary piles with steel beams, then backfilled them with concrete before constructing cast-in-place walers. Each waler sandwiched the head of a ground anchor, which had been installed using custom reach-over excavators mounted on drill rigs. To mitigate grout overrun, FDT incorporated grout socks around the anchors.