Abstract: A box type duct with circumferential obtuse angle connection. Unit plates respectively located on the upper, lower and two side surfaces are spliced in the circumferential direction to form a unit pipe section, and the unit pipe sections are spliced in the axial direction to form a box type duct; wherein the unit plate is an arc-shaped corrugated plate arched to the outside of the box type duct, and the adjacent unit plates form an obtuse angle of circumferential connection. The cross section of the duct is in an approximately rectangular box shape, so the utilization ratio of clearance of the duct is high; the unit plate adopts an arc-shaped structure, and by utilizing the pipe-soil joint stressing principle, the strength and bearing capacity of the overall structure are maximized; and the box type duct adopts flat flange or angle steel flange connection in the circumferential direction.

Abstract: A large-aperture spiral welded steel pipe with metal linings and a manufacturing method thereof, wherein the pipe includes a pipe body spirally winded by a main steel belt; a first lining and a second lining are arranged on a body inner wall, the first lining is spirally laminated on the main steel belt surface, the first lining width is smaller than the main steel belt width, the second lining is spirally laminated on a spiral seam formed between adjacent pipe bodies, the second lining left and right sides are respectively welded with the adjacent first lining, and the first lining and the second lining cover the inner wall of the entire body; and a reinforcement ring with a semi-closed section is spirally arranged along a body outer wall, and a spiral passage is formed between the inner wall of the reinforcement ring and the body outer wall.

Abstract: An underground steel-concrete structure pipeline with a spiral composite reinforcement ring on an inner wall and a manufacturing method thereof. The pipeline includes a pipe body, multiple rows of concrete overflow holes spirally arranged on a pipe wall of the pipe body, a reinforcement ring capable of wrapping the concrete overflow holes, and concrete is filled in a hollow cavity between the reinforcement ring and the pipe wall to form a spiral concrete flow passage. The advantages are that the overall annular strength of the pipeline is reinforced by the reinforcement ring; the concrete filled between the reinforcement ring and the inner wall of the pipe body improves the compressive strength of the pipe body; the concrete overflowing from the overflow holes on the pipe wall combines the pipe body with a pit; and the pipeline solves the difficulty of using large-size steel structure products in underground common pipeline projects.

Abstract: A large-aperture spiral welded steel pipe with metal linings and a manufacturing method thereof, wherein the pipe includes a pipe body spirally winded by a main steel belt; a first lining and a second lining are arranged on a body inner wall, the first lining is spirally laminated on the main steel belt surface, the first lining width is smaller than the main steel belt width, the second lining is spirally laminated on a spiral seam formed between adjacent pipe bodies, the second lining left and right sides are respectively welded with the adjacent first lining, and the first lining and the second lining cover the inner wall of the entire body; and a reinforcement ring with a semi-closed section is spirally arranged along a body outer wall, and a spiral passage is formed between the inner wall of the reinforcement ring and the body outer wall.

Abstract: An underground steel-concrete structure pipeline with a spiral composite reinforcement ring on an inner wall and a manufacturing method thereof. The pipeline includes a pipe body, multiple rows of concrete overflow holes spirally arranged on a pipe wall of the pipe body, a reinforcement ring capable of wrapping the concrete overflow holes, and concrete is filled in a hollow cavity between the reinforcement ring and the pipe wall to form a spiral concrete flow passage. The advantages are that the overall annular strength of the pipeline is reinforced by the reinforcement ring; the concrete filled between the reinforcement ring and the inner wall of the pipe body improves the compressive strength of the pipe body; the concrete overflowing from the overflow holes on the pipe wall combines the pipe body with a pit; and the pipeline solves the difficulty of using large-size steel structure products in underground common pipeline projects.