Sequential Excavation Method
First developed in Austria, the Sequential Excavation Method (SEM) is a tunneling technique that鈥檚 gained significant traction in the United States. We鈥檙e well versed in this innovative technique, having completed numerous tunnels, subways and stations using this approach. Properly executed, the method allows for the construction of large and complex caverns using conventional equipment and materials, with very little surface settlement. It鈥檚 also the most resistant tunnel support system in earthquake endangered zones.