94results about How to "Solve length" patented technology

The invention discloses a shallow-buried underground excavation construction method for arc-shaped variable-section tunnels in rock-filled strata. The shallow-buried underground excavation construction method includes steps of excavating and constructing first vertical shafts and second vertical shafts; building first-group pipe sheds in the first vertical shafts until the first-group pipe sheds reach second pipe shed work rooms, and building second-group pipe sheds in the second vertical shafts until the second-group pipe sheds reach first pipe shed work rooms; carrying out underground excavation construction until the second-group pipe sheds reach the first pipe shed work rooms; changing pipe shed construction directions in the first pipe shed work rooms and building third-group pipe sheds; lapping top pipe sheds of the third-group pipe sheds with the first-group pipe sheds and allowing lateral pipe sheds of the third-group pipe sheds to exceed the second pipe shed work rooms and completely carrying out advanced pipe shed support on the second pipe shed work rooms; carrying out underground excavation construction until the third-group pipe sheds reach the second pipe shed work rooms; building lateral pipe sheds of fourth-group pipe sheds in the second pipe shed work rooms and completely carrying out advanced pipe shed support on arc-shaped widened section tunnels. The shallow-buried underground excavation construction method has the advantages that the pipe shed work rooms are set, the pipe sheds of the arc-shaped variable-section tunnels are built and lapped in oppositedirections, and accordingly the difficult problem of incapability of constructing advanced pipe sheds when shallow-buried underground excavation construction is carried out on existing arc-shaped variable-section tunnels can be solved by the aid of the shallow-buried underground excavation construction method.