Tunneling | Granite Construction

National Leader in Rapid Tunnel Technology

Granite is a national leader in tunneling, completing more than $1 billion in tunnel projects in the last 10 years alone. Constantly innovating, Granite has developed leading tunneling technologies, such as the first continuous horizontal and vertical muck removal system, which greatly increases speed while maintaining the highest levels of safety.

Rapid Tunnel Technology

As the first contractor in the world to mine hard rock with a 30-foot diameter Tunnel Boring Machine (TBM), Kenny has highly automated the entire tunneling process, reducing tunneling costs. In predominantly urban applications, tunnel boring is a quick, safe and cost-effective alternative to laying surface rails and roads.

Tunnel Construction Methods

Factors such as soil conditions, groundwater conditions, length, diameter and depth of the tunnel are assessed by in-house tunneling experts. We skillfully perform cut-and-cover, bored tunnel, drilling and blasting techniques for both transit and utility tunnels.

Miner’s Luck: Naming the TBM

Naming TBMs with a female name has been a mining tradition for Saint Barbara, the patron of miners, to protect workers as they work underground. In keeping with tradition, tunneling machines are still named before the digging begins.

Queens Bored Tunnels and Structures - NY

One of the most challenging tunnel projects in New York City’s recent construction history, the $720 million dollar project consisted of excavation and precast concrete lining of four bored tunnels and an emergency exit shaft, directly under an existing active railyard in the heart of Queens. Mining continued while 800 trains passed through the yard above daily.

Brightwater Conveyance East Contract - Seattle, WA

As part of a $705 million wastewater conveyance system, three separate tunnels were dug using an earth pressure balance machine (EPBM) to bore a tunnel 18 feet in diameter to a depth of 260 feet below the surface. The project lies near the north end of the Seattle Basin, composed of sands, silts, fine gravels and silty fine sands, some under high artesian pressure.

North Outfall Sewer – Los Angeles East Central Interceptor

This new interceptor system, approximately 60,000 lineal feet in length, required four new 15.5-foot diameter EPB TBMs mining concurrently. The tunnel was particularly risky in segments where the water table was well above the tunnel, as well as where geologic faults crossed with special concerns for seismic disruption. Watertight construction techniques and primary lining were paramount.

39th Street Conduit Rehabilitation Phase 1 Bypass Tunnel - Chicago, IL

The project for the Metropolitan Water Reclamation District consists of approximately 15,000 linear feet of 15-foot diameter lined tunnel. It also includes a connection to an existing TARP tunnel stub, six lined drop shafts with inside diameters varying from seven feet to 15 feet and 250-foot depths.

Goodbye For Now