Tunnel formation process involves placing tunneling device into well formed in transition zone between two tunnel sections, and modifying diameter of second tunnel section by performing excavation using tunneling device

摘要

The method involves forming a first vertical well in the transition zone between the first section and second section of a tunnel, and placing a tunneling device into the first vertical well. The tunneling device is used to modify diameter of the second tunnel section by excavating the second tunnel section until suitable and greater diameter is reached.