US 4,124,985 A · Collapsible tunnel liner section and method of lining a tunnel

Abstract

A collapsible concrete tunnel liner section formed from a number of arcuate segments each connected together by hinges to form a closed loop. In collapsed condition the segments are arranged in a compact stack having a cross section less in its maximum dimension than the internal diameter of the erected liner section. Typically the stack has the appearance of a figure 8, having upper and lower cavities. Air bags are located within these cavities and are expanded to expand the collapsed tunnel liner section into its erected condition. During the expansion the liner section passes through an oversized condition before assuming its final erected condition. This ensures stability for the erected liner section. After erection, grout or other filler material is inserted between the liner section and the wall of the tunnel.

Claims11

Dependent claims

A collapsible concrete tunnel liner section comprising:

(a) at least six arcuate concrete segments forming, when erected, a closed loop tunnel liner section of predetermined inner diameter,
(b) hinge means hingedly connecting said segments together for movement from a collapsed condition in which said segments are arranged in a compact closed loop stack having an external cross section less in its maximum dimension than said predetermined diameter, through an intermediate position in which said segments are partly erected and have an interior cross section having a maximum dimension greater than said predetermined diameter, to an erected condition in which said segments form said closed loop tunnel liner section, and
(c) expandable air bag means within said stack for expanding and thereby expanding said stack from said collapsed condition through said intermediate condition to said erected condition.

Dependencies are inferred from the claim text.

Collapsible tunnel liner section and method of lining a tunnel

Life of this patent

Collapsible tunnel liner section and method of lining a tunnel

Life of this patent

Abstract

Claims11