Alex Folchi, PE
Alex presents over 15 years of experience in the heavy civil construction industry, with nearly a decade of that time at Drill Tech. While his design capabilities include an array of foundations/ground improvement (CIDH, micropiles, augercast piles, CSM) and shoring (soil nail walls, tiebacks, secant pile walls), Mr. Folchi is especially skilled in underground work. This has included excavation through SEM, or NATM, and drill/blast techniques on high-profile tunneling and shaft projects. The projects outlined below are just a few of his recent projects within this scope.
Alex's Featured Projects
OID Paulsell Lateral Tunnels 1&2 | Oakdale, CA
Project Manager
Drill Tech performed roadheader excavation for tunnel expansion of Oakland Irrigation District’s Paulsell Lateral Tunnels 1 and 2. In total, just over 1,000 LF of tunnel underwent enlargement from 3′x7′ to 9′x10′ with AM-50 size roadheaders mining both tunnels at once. Prior to underground excavation, Drill Tech installed a soil nail shotcrete portal at the end of each tunnel. Drill Tech acted as the General Contractor, handling all shotcrete, spoils site management, as well as environmental/SWPPP management with multiple strict environmental regulations and restriction of construction times depending on the weather.
Helms Tunnel Liner Repair | Shaver Lake, CA
Project Manager
Drill Tech acted as the General Contractor on this repair project for PG&E’s Helms Pumped Storage System. The major scopes included contact grouting of steel and concrete penstock liners, acrylic stitch grouting, spalled concrete removal/replacement, and drain/decompression hole installation. Roughly 1,000 LF of leaky water tunnel was dewatered, and a 50′ deep drain hole was decommissioned by hand in extremely low overhead. Drill Tech carried Tunnel Safety Order operations, provided all tunnel utilities, and oversaw other third parties in contract with PG&E during this project. With the site location’s logistical challenges, there were several innovations that enabled the successful completion of this project.
Caltrain Tunnel Modifications for Electrification Project | San Francisco, CA
Project Manager
This project consisted of the enlargement and electrification of four existing Caltrain double track train tunnels in the San Francisco and San Francisco area: Tunnel 1 is 1800' long, Tunnel 2 is 1100' long, Tunnel 3 is 2360' long, and Tunnel 4 is 3600' long. Drill Tech executed a variety of scopes on all four tunnels, the main scope including the use of a rail mounted roadheader to perform tunnel notching that allowed larger electrified trains to fit a larger envelope and achieve the required additional clearance. Drill Tech installed overhead anchors to hold the future OCS wires into the tunnel liner. At each portal (2 per tunnel; 8 total) a larger steel structure was erected on top of either OCS foundations or micropiles. These OCS Portal structures helped hoist the OCS line running through the tunnels, and the OCS wires and conductor rails were then installed.
River Valve Outlet System | Oroville, CA
Project Manager
This project is part of the Department of Water Resources’ larger plan to upgrade Oroville Dam since its spillway damage in 2017. This site presented logistical challenges with access that required innovations of utilizing specialty equipment, such as a multi-point articulating specialty drill mast mounted on a mini excavator. Drill Tech installed rock anchors / stich dowels for the new concrete thrust block, design-built temporary rock anchor shoring for the tunnel’s concrete liner removal, and provided other scopes including extra grout work that was added as DWR encountered unknown water seepage concerns. Drill Tech also provided consultation on Tunnel Safety Order support, recommendations, and regulations.
