Project Description

The Johnson Creek Interceptor is a 90,000 ft long interceptor sewer. 2,300 feet of 54" diameter sewer was constructed by microtunneling. This portion of the project was located adjacent to the Texas Rangers Ball Park, and ran beneath parking lots. Microtunneling was also used to construct two additional sections, each several hundred feet in length, permitting the 54" pipeline to cross under Interstate 30 and State Highway 360.

These tunnels were constructed in the mixed sedimentary rock of the Woodbine formation. This formation presents extremely challenging tunneling conditions, consisting of unconsolidated sands, clays, sandstones and shales. It also can contain isolated beds of very hard rock. These conditions are frequently expressed as mixed face tunneling conditions, and the unconsolidated sands can contain pressurized groundwater.

Scope of Services

LACHEL & Associates, Inc., participating on a team lead by Carter-Burgess, specified and interpreted geotechnical borings, developed interpretive geologic cross sections for the bid documents and characterized rock conditions for tunneling and shaft construction. Microtunneling methods were selected for construction of the tunneled sections. These methods were applied to successfully overcome some groundwater and hard rock challenges which were encountered.

Client

City of Arlington, Texas