The construction site of the China Beishan Underground Laboratory project, located in Mazongshan, Subei County, Gansu Province, shows a horizontal turning radius of 200 meters and a vertical curve radius of 380 meters, and will move forward in a spiral manner at a depth of 590 meters underground. On May 29, 2023, China's independently developed large slope spiral tunneling machine, Beishan No.1, successfully turned for the first time.

At present, the reliability of the design schemes for long-distance extremely hard rocks, small radius spiral turns, and large slope and long-distance downhill slopes has been preliminarily verified, marking a significant breakthrough in the application of achievements in this technological innovation field in China. The main engineering ramp of the Beishan Underground Laboratory in China has entered a rapid construction phase.

The geological conditions of the Beishan underground laboratory in China are mainly composed of slightly weathered granite, with a quartz content of 25% to 30%. The uniaxial saturated compressive strength of the rock exceeds 260 MPa, exceeding the standard for general hard rocks by 200 units. It belongs to extremely hard rock geology with high construction difficulty. Among them, the spiral ramp project is a key main project of the laboratory, with a total length of about 7.2 kilometers. It is excavated clockwise from the surface, with a comprehensive slope of 10%. For every 10 meters of tunnel excavation forward, the height decreases by 1 meter.

Beishan No.1, jointly built by China Railway Construction Heavy Industry Group and China Railway 18th Bureau Group, is the world's first large gradient spiral tunnel boring machine, with a length of about 100 meters and a diameter of 7.03 meters, which can solve the problem of spiral small turn tunneling in continuous large gradient tunnels. Editor/Xie Li