Construction of tunnels for various purposes
The technology of tunnel construction with in-situ pressed lining is based on the principle of forming permanent lining behind shieldtail skin as the shield moves to the face, with the lining closely abutting the ground around the contour and preventing ground displacement inside the opening. Tunnel shields for construction of in-situ pressed lining should meet some requirements, determined by an adopted technological scheme. In all technological schemes, spoil from a shield is transported through concreting zone by a conveyor, which provides continuous spoil removal, does not take up much room in the tunnel, is simple in design and is isolated from the other equipment by housing or cover. The mobile guard ring consists of composite components connected by hinges. Typical independent hydraulic circuits for drives of mechanized shield machines and devices for main tunneling operations, including those associated with in-situ pressed linings, are adopted on the strength of experience of design, manufacturing and development of hydraulic drives for tunnel shields.