Pipe roofing machine, a new-type trenchless construction technology, is used for pre-supporting the soil on the?periphery?of the tunnel face by building pipe roofs to guarantee that the excavation can be conducted safely. This method is often applied for the tunnel which passes through existing highways or railways.

Working principles of pipe roofing machine

Steel tubes are jacked into the soils between the launching shaft and the reception shat by a pipe jacking machine. Steel tubes are connected each other by lock mouths to form a complete tube. Water-proofing additives are injected into the gap between the tube and the surrounding soil to prevent water from entering the tunnel. When the construction of steel tube is completed, pre-support is formed. Under the protection of pipe roofs, the tunnel can be excavated safely. 

                                                        Diagram of pipe roofing construction

Features of CRCHI¡¯s pipe roofing machine

- a composite cutterhead is capable of cutting artificial fill, mudstone, sandstone and other complicated geologies.  

- thanks to the function of being pulled out, the machine is suitable for the project without reception shaft and can be used more than once. Therefore, when encountered with obstacles, people can enter the tunnel to deal with obstacles after the machine is pulled out.  

- the machine uses slurry balance method for slurry discharge, leading to high precision control of tunnel face pressure and reduced ground settlement. And its slurry circuit system is equipped with flow meters and pressure sensors, resulting in increased precise control.   

- equipped with an automatic measurement system which realizes accurate measurement and feedback for machine posture.

- equipped with an articulation device which allows for precise deviation correction and accurate direction adjustment.

Application

CRCHI's pipe roofing machine for Chongqing Railway East Loop Project

Pipe roof tunnels excavated by CRCHI's pipe roofing machines

China Railway Construction Heavy Industry Corporation Limited (CRCHI)

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