Heard of horizontal, vertical shaft

or even inclined shaft tunneling

But

have you ever seen a TBM

that excavates upward at a large elevation angle

like a 'dragon raising its head'?

A magical machine arrives

Watch now

Recently, at the construction site of the State Grid Xinyuan Hunan Pingjiang Pumped Storage Power Station, the variable diameter inclined shaft rock tunnel boring machine (TBM) independently developed by CRCHI successfully completed the world's first R50m ultra-small vertical curve, also excavating upward at a large elevation angle like a 'cobra maneuver', and entered the 50° inclined shaft section for excavation, marking another major historic breakthrough in China's TBM technology.

Vertical curve section formed by TBM tunneling

It is reported that the water diversion inclined shafts of pumped storage power stations are usually arranged in two stages, each about 500m long, and between the horizontal tunnel and the inclined shaft there is a sharp transition curve of about R50m. In previous TBM development and application, the minimum vertical curve turning capability of TBMs was typically between R500 and R1000m. For the sharp and large gradient change required by the water diversion inclined shafts of pumped storage power stations, an R50m vertical curve means that for every 0.5m of tunneling, the cutterhead elevation angle can reach up to 1.2°. Previously, domestic and international peers have stated that this is difficult for TBMs to achieve.

With its strong technical accumulation, CRCHI, after successively overcoming technologies such as large-gradient tunneling for coal mine TBMs and horizontal turning for drainage gallery TBMs in pumped storage power stations, with the support of State Grid Xinyuan Hunan Pingjiang Pumped Storage Company, jointly with Sinohydro Bureau 8 Co., Ltd., PowerChina Zhongnan Engineering Corporation Limited, and Guangdong Keyuan·Hunan Electric Power Consulting Consortium, independently developed a series of key core technologies. They have completed the development and application of more than ten key core technologies, including the vertically turnable TBM shield body, variable zoning stepless back pressure regulation hydraulic propulsion system, laser + multi-sensor fusion TBM guidance measurement system, adaptive variable head fluid medium transportation technology, multi-stage variable slope mucking technology, and rapid launch technology without turning guide platform.

50° ultra-large gradient working condition

It is understood that the R50m turning tunneling of the variable diameter inclined shaft TBM, with the joint efforts of all participating parties, overcame many difficulties such as complex transportation routes with many curves and steep slopes in the tunnel, narrow lifting space in the 60m assembly cavern, assembly and commissioning period of only 40 days, complex split launch procedures, and various challenges in tunneling, mucking, guidance, and material transportation during the turning process. The turning section tunneling was completed in only 19 days, with a maximum daily advance of 5m, greatly shortening the horizontal-to-inclined transition period of the inclined shaft TBM, and creating favorable conditions for the subsequent rapid construction of the straight section of the water diversion inclined shaft of the Pingjiang Pumped Storage Power Station.

Equipment assembly site in the tunnel