Apparatus and Methods for Underground Structures and Construction Thereof

An underground structure comprising:

• a plurality rings creating an enclosed area defined by a first end and a second end and an internal diameter, wherein each ring includes a plurality of segments the define the internal diameter, and
• at least one post-tensioning cable configured to hold together the plurality of segments within each ring, wherein the at least one post-tensioning cable runs through a first conduit in the plurality of segments.