Innovative Equipment for Tunneling Operations
03/18/2025
By John Kuka
Director of Business Development, Engineered Rigging
When an operation requires lifting, lowering or lateral movement of heavy loads underground, there are often complex challenges to consider. Limited headroom often precludes a traditional lifting solution, such as a crane; concerns over air quality need to be considered; and portability is often a driving force in selecting the right equipment. When considering these challenges, high pressure hydraulic equipment is often the best solution.
The type of tunneling task will dictate which equipment is suitable. Strand Jacks, Cube Jacks and Hydraulic Gantries have proven to be excellent options for lifting and lowering projects, whereas Skidding Systems, Turntables, Hydraulic Cylinders and Split-Flow Pumps are contenders for the lateral movement of tunnel boring machines (TBMs) during placement and maintenance.
Figure 1: Low-Height Skidding System Used in Placement of TBM
Placement of Tunnel Boring Machines
TBMs (pictured at top of article) are commonly used to construct tunnels for mining, high-speed trains, subways, railways, roadways, stormwater and sanitation systems. According to the American Society of Mechanical Engineers, TBMs “excavate through dirt and solid rock, carry away the materials and install concrete. These pressurized machines not only create the tunnel but line the walls behind them with a watertight combination of grout and precast interlocking concrete blocks.”
There are a few types of equipment that are suitable for moving these huge machines into position. In Ohio, a TBM weighing 370 tons required a horizontal move down nearly 1,200 feet of shaft before it could begin its work. There was a twist, though, as the machine had to be rotated 62 degrees at the midpoint of the shaft. A Low-Height Skidding System was used to transport the TBM (see Figure 1) and a Hydraulic Turntable provided the rotational function. In addition, eight high-tonnage Hydraulic Cylinders and two Split- Flow Pumps helped lift and lower the TBM onto the transport frame.
In California, a Micro TBM weighing 90 tons needed to be laterally transported inside of an existing mining shaft and then placed on a frame to begin its work. Similar to the Ohio tunneling project, Engineered Rigging provided a Low-Height Skidding System for horizontal transport. Once the load reached the tunnel face, a Cube Jack System (see Figure 2) was employed to lift the machine into its frame. Cube Jacks’ simplified operation sequence has 50% fewer cycles than Climbing Jacks, and the lightweight, self-aligning steel cribbing blocks save time, improve side load and eliminate the need for wooden cribbing materials. Cube Jacks feature a lifting height of nearly 10 feet and a small footprint ideal for lifting loads in tight spaces—like a tunnel.
Figure 2: Enerpac Cube Jack System
Equipment Maintenance
As with any type of heavy-duty equipment, TBMs require regular maintenance to optimize safety and performance. One of the most essential components of a TBM is the cutter head that rotates through soil and rock to propel the machine forward, leaving a tunnel in its wake.
When a TBM arrived in Cuyahoga Heights, Ohio, for Project Clean Lake, an initiative to reduce water pollution in Lake Erie, the cutter head required refurbishment before it could be used. To conduct the routine maintenance, the head, which weighed 55 tons and touted a 14.5-foot diameter, needed to be removed from the mounting ring on the machine.
After carefully assessing the load requirements and site specifications, our engineers designed a lift plan that featured an Enerpac SL60 Hydraulic Gantry System. With a 60-ton load capacity and compact footprint, the system included a gantry, 6-meter header beams, static lifting lugs and seven pieces of gantry track. This project was successfully completed in September 2024.
Figure 3: Enerpac Strand Jack
Lowering Operations
In the mining industry, raise boring machines are often used to provide ventilation or escapeways. When created, they require a series of liner “cans” to be lowered into the shaft to create a permanent structure. Strand Jacks can lower the liners inside of the shaft segmentally attaching to custom-fitted frames and mechanically holding them in place while they are grouted into position. Strand jacks are compact, easy to transport and setup, which makes them ideal for projects in remote locations.
A gantry was also used inside a tunnel in Chile during the construction of the Alto Maipo Hydropower Plant (see figure 3). As construction of one of the tunnels was nearing completion, an overhead construction crane needed to be dismantled and removed. The crane weighed 80 tons, was 8 meters high and 9 meters long. For this project, a heavy-duty Super Boom Lift SBL500 Hydraulic Gantry was used. Read the Case Study.
Figure 4: Gantry Lowers Crane inside of Tunnel
Tunneling Equipment Solutions
High pressure hydraulic equipment is often the best solution to address the challenges presented by operations in an underground environment. This equipment provides lifting, lowering and horizontal movement in areas where limited headroom, equipment portability, and ease of operation are driving factors in equipment selection. If you’re uncertain of the best solution for a specific project, our heavy lifting experts are available to help at sales@engineeredrigginggroup.com or 844.474.4448.
