On September 4, 2022, the world's first large-slope spiral tunnel boring machine jointly built by CRCC and China Railway 18th Bureau rolled off the assembly line in CRCC Changsha Second Industrial Park.

This tunnel boring machine is named "Beishan No. 1". The equipment needs to excavate a spiral curve ramp in the Beishan underground laboratory. The project is driven in a clockwise spiral from the surface down. The comprehensive slope is 10%, which is equivalent to every forward direction of the tunnel. The excavation is 10 meters, and the height is lowered by 1 meter.

The Beishan underground laboratory slope is about 7.2 kilometers long. It is the first slope project in the world to be constructed with a full-section rock boring machine. During the construction, it is necessary to solve the problem of equipment in the continuous large-slope tunnel with spiral and small turns. Mainly complete granite, the quartz content reaches 25%-30%, and the maximum uniaxial saturated compressive strength of the rock is as high as 230 MPa, which belongs to extremely hard rock geology with difficult construction.

The spiral slope of the main project of the China Beishan Underground Laboratory was constructed by the China Railway 18th Bureau. "Beishan No. 1" was successfully rolled off, marking that the Beishan underground laboratory is about to enter the rapid construction stage of the slope, which will effectively boost the construction progress of the Beishan underground laboratory.Editor/Ma Xue