Michael Cox, PE
Michael has been a Project Manager with Drill Tech for 20 years and is also currently the Director of Operations for our Subsidiaries. His extensive experience in the heavy civil construction industry has included estimating, design and oversight of a variety of scopes including soil nails, micropiles, and soldier piles. Mr. Cox has managed several major tunneling and shaft projects that utilize a variety of excavation methods.
Michael's Featured Projects
Lenihan Dam Outlet Modifications and Inlet Shaft | Los Gatos, CA
Project manager
This project consisted of a 2,035’ long, 14' diameter horseshoe-shaped tunnel excavated with a combination of roadheader and drill/blast through a Franciscan Mélange material ranging from extremely hard rock to crushed clay. The tunnel was adjacent to and under an active reservoir and required extensive probe hole drilling, spiling, and cut-off grouting. After driving the tunnel, Drill Tech installed a final cast in place concrete lining and a 54” diameter outlet pipe in the tunnel. The tunnel was connected to the surface of the lake by a 16' inside diameter, 50' deep, shaft that was lined with secant piles and constructed less than 10 feet from the lake’s edge.
Cal Park Hill Tunnel Rehabilitation and Appurtenances | San Rafael, CA
project manager
This Drill Tech contract rehabilitated a 1100' long, 31' diameter horseshoe-shaped railroad tunnel. Operations consisted mostly of the demolition and replacement of broken tunnel supports in highly fractured rock conditions as well as wet, mixed face conditions with short initial standup time. This project also required 160' of re-mining through a completely collapsed section of tunnel, “cut and cover” operations, and temporary support of existing sink holes that reach to the surface. The existing redwood sets that had been rotting were replaced with W8x31 steel sets and the tunnel was then lined with more than 5000 CY of steel fiber reinforced shotcrete to complete the ground support. The project also included a pedestrian pathway that has all the elements of building construction (i.e. CMU wall, steel erection, architectural, electrical and mechanical works).
Clos de la Tech Winery & Storage Tunnels | Woodside, CA
project manager
Drill Tech was contracted by a private owner to design and construct an underground complex to house an entire winery underground in a steep hillside location south of San Francisco. This work required soldier pile walls, soil nail walls up to 50 feet tall at the portals, three main tunnels 300' long up to 34' in diameter, nine smaller tunnels, a 30' diameter shaft, and multiple drilled vent shafts to 4' in diameter, 120' deep. The tunnels were driven through very difficult mixed ground under shallow cover, requiring a mix of excavator, roadheader and drill/blast excavation with extensive spiling. The tunnels were supported, in various locations, with steel sets, rock bolts and shotcrete, and lattice girders and shotcrete. Most of the shotcrete surfaces were carved and stained to resemble the natural rock.
