Transforming the World Around Us

The Regional Connector consists of twin underground tunnels approximately 1.9 miles long and more than 50 feet below grade that connect several of Metro’s existing light rail lines to provide better connectivity and more efficient rail service in the downtown area. The twin tunnels were constructed with the use of earth pressure balance (EPB) type tunnel boring machines (TBM). Concrete segment liners were used as primary support of the tunnel excavations which were assembled within the tail shield of the TBM as the shield advanced forward. Ninyo & Moore provided geotechnical instrumentation monitoring services for this project to help manage risk and liability to the owner due to the tunneling and excavation construction.