Large Diameter Tunneling

It’s where SAK began.

And another service where we continue to lead.


Starting in the 1960s, SAK’s tunneling team literally built the modern tunneling industry from the ground up. Led by industry veterans Bob Affholder and Jerry Shaw, SAK ranks among the most experienced and best-equipped tunneling contractors in the United States. And we’re proud to serve customers in the municipal, energy, and industrial sectors, providing a range of solutions for water, sanitary and stormwater pipeline.

When your situation calls for complex pipeline expansion or simple repair, trust SAK to expertly excavate tunnels from 4-foot diameter to 32-foot arch-shaped SEM tunnels in all kinds of ground conditions, including soft-ground, soft-rock, hard-rock, and hand-mined. Watch it in action here.


Deep experience. Broad resources.


municipalheader.pngSAK is ready for your most challenging underground projects. Having managed many multi-million dollar complex projects, SAK’s tunneling teams bring years of hands-on experience and a broad range of technologies to solve every challenge. Our large-diameter tunnel expertise makes SAK the right choice for a range of sewer line, water line or storm drain installations as well as projects outside the scope of auger-boring or conventional open-trench construction. And we’ll work with you literally every foot of the way to minimize the impact to your business, your community, and your crews.

  • Soft-Ground Tunneling: Made up of various mixtures of clay, silt or sand, soft-ground ranges in consistency from “firm” to “running.” In these conditions, SAK can implement a variety of solutions including hand mining, slurry pressure balance tunnel-boring machines, and earth pressure balance machines. Soft-ground methods are suitable for tunneling for sanitary and storm sewers and highway, mass transit, utility, and pedestrian tunnels.
  • Soft-Rock and Hard-Rock Tunneling: Soft rock comes in many forms, including varieties of mudstone, siltstone, sandstone and shale while common types of hard rock include granite and limestone. When faced with hard or soft rock, SAK employs drill-and-blast and open main beam methods, plus single shield and double shield tunnel- boring machines. Applications include construction of sanitary and storm sewers, and water, highway, mass transit, utility and pedestrian tunnels.
  • Hand-Mined Tunneling: Using liner plate, rib-and-board and timber sets to support the soil or rock, SAK has successfully completed hand-mined tunnels of various shapes and sizes through a range of soil types. Common applications for hand mining include starter tunnels, tail tunnels, utility tunnels, road crossing tunnels, and connecting tunnels for structures.

Leaders then. Leaders now.  

With a century of combined experience in tunneling and trenchless pipeline rehabilitation, your SAK team will draw on a variety of technologies to devise the perfect solution for your unique pipeline challenges.