Curved tunnel extends limits of microtunneling
Congratulations to our crew and project partners for extending the limits of microtunneling technology. Michels completed an exceptional 470-foot drive under the Tualatin River in Tualatin, OR in less than a month. The 84-inch diameter tunnel features a vertical “U” curve with a 650-foot radius – a North American record for the tightest curve radius at this diameter.
Michels used a new Herrenknecht AVN 1800 machine with double-steering articulation to navigate the radius of the curve and a jacking system to install a specialized reinforced concrete pipe.
The microtunneling drive is part of a design-build project being executed with Mortenson for Clean Water Services.