Drive shaft, work shaft, exit shaft. The excavated pit by which appropriate trenchless method is used. The size of the shaft is based on the trenchless method selected. Shaft types include Trench Box Shoring, Soldier Pile/Plate, Soldier Pile/Timber, Sheet Pile with Waler or Ring Beam Support, Liner Plate with Ring Beam Support, and Secant Pile.
Hand Mine Tunneling is a method of tunneling that uses hand tools to install a tunnel in stable ground conditions. This method is primarily used on short drive lengths (less than 150 FT) ranging in size from 36” to 144” where work areas for support equipment is approximately 50×100 (5000 SF). Tunnel liners installed by this method include steel casing, tunnel liner plate, reinforced concrete pipe, fiberglass reinforced pipe, and wood box tunnel.
Microtunneling is a method of tunneling that uses remote guidance (non-man entry), pipe jacking, and water jetting to excavate during the tunneling process in all types of soil conditions. This method is primarily used on drive lengths exceeding 300 FT in length for tunnels ranging in size from 36” to 120” where work area for support equipment is approximately 10000-15000 SF. Tunnel liners installed by this method are casing, fiberglass reinforced pipe, and concrete pipe.
Mechanized Tunneling is an advanced construction method that employs tunnel boring machines (TBMs) to excavate and install tunnels efficiently across a wide range of soil conditions—including soft soils, mixed ground, and hard rock. This technique is especially well-suited for longer drive lengths, typically exceeding 300 feet, and is commonly applied to tunnels ranging in diameter from 72 inches to 144 inches.
Due to the scale and complexity of this method, it requires substantial support space, with work areas typically ranging from 10,000 to 15,000 square feet to accommodate staging equipment, spoil removal systems, and TBM operations.
Various types of tunnel liners can be installed using mechanized tunneling, including steel casing, tunnel liner plates, precast concrete pipe segments, and rib-and-lagging systems. These liners provide structural integrity and long-term durability, making mechanized tunneling a reliable and efficient choice for large-scale infrastructure and utility projects.
