China

Challenging Drive at China’s Yin Han Ji Wei Water Diversion Project Completed

An 8 m diameter Main Beam TBM broke through at China’s Yin Han Ji Wei project in the first quarter of 2022. The project is considered to be one of the most challenging ever completed by a TBM, with crews encountering abrasive hard rock, over 14 000 rock bursts, and multiple severe water inflow events. The machine overcame 17.5 km of tunnel in some of the most difficult geology ever encountered. The water diversion tunnel traverses the Qinling Mountains of Shaanxi Province, with up to 2000 m of cover.

An 8 m diameter Main Beam TBM broke through at China’s Yin Han Ji Wei project in the first quarter of 2022. The project is considered to be one of the most challenging ever completed by a TBM
Credit/Quelle: Robbins

An 8 m diameter Main Beam TBM broke through at China’s Yin Han Ji Wei project in the first quarter of 2022. The project is considered to be one of the most challenging ever completed by a TBM
Credit/Quelle: Robbins

The ground, consisting of mainly quartzite and granite, was estimated to have a rock hardness of between 107 and 309 MPa UCS, with high abrasivity and a maximum quartz content of 92.6%. During tunneling, the crews of the China Railway Tunnel Group (CRTG) encountered over 14 000 rock bursts, some with energy as high as 4080 kJ. Water ingress occurred a total of 69 times during the drive, with some inflows extremely high – exceeding 20 000 m3 of water in one day from a single point. In-tunnel ambient temperatures peaked at 40 degrees Celsius and 90% humidity.

During tunneling, crews encountered over 14 000 rock bursts, some with energy as high as 4080 kJ
Credit/Quelle: Robbins

During tunneling, crews encountered over 14 000 rock bursts, some with energy as high as 4080 kJ
Credit/Quelle: Robbins

Throughout the challenges, the crew found ways to persevere. Rock bursting was controlled using steel slats in conjunction with the McNally crown support system, while zones of stress were predicted using a micro-seismic monitoring system. The micro-seismic system records rock stresses in a borehole 20 m ahead of the face and predicts the potential for rock bursting following comparative analysis with similar rockburst data from other projects, as well as from nearby sections of tunnel in the Qinling Mountains.

Water ingress was controlled by dramatically increasing pumping capacity in the tunnel to 41 000 m3 per day. Systematic probing ahead of the TBM was also used to detect water, as well as rock bursting. When ingress exceeded 70 percent of the in-tunnel pumping capacity, crews then carried out grout injections.

With TBM tunneling complete, the route will become part of two other sections of an altogether 82 km long tunnel that will link up the Hanjiang and Weihe Rivers in Shaanxi province. The completed tunnel, for owner Hanjiang-to-Weihe River Valley Water Diversion Project Construction Company, will secure a water supply for towns and agricultural areas in Central China, while also generating hydroelectricity.

x

Related articles:

Issue 2021-02 China

China’s Largest Robbins Crossover TBM Launches on Pearl River Delta Intercity Railway

The largest ever Robbins Crossover (XRE) TBM in China launched in late March 2021 in Guangzhou for contractors Sichuan Jinshi Heavy Equipment Leasing Co., Ltd and CREC Bureau 2. The 9.16 m diameter...

more
Issue 2016-06 Lebanon

Great Beirut Water Supply Project: First of Two Hard Rock Tunnel Boring Machines in Operation

A number of years ago the Great Beirut Water Supply project (GBWSP) was established to improve the drinking water provision of the greater Beirut area and strengthen the weakly structured southern...

more
Issue 2011-01 China

Hard-Working TBM breaks through at Pinglu Tunnel

A veteran Double Shield completed one of the world’s longest single-drive TBM tunnels, at 25.4 km (15.8 mi), on November 14, 2010 (Fig. 1). The 4.8 m (15.7 ft) diameter machine bored the Pinglu...

more
Issue 2015-06 Lebanon

CREG signed two Gripper TBMs to Beirut Water Supply Tunnel Project

On July 17, 2015, the Italian construction contractor CMC and TBM manufacturer CREG signed a procurement contract of supplying two Gripper TBMs with a diameter of 3.5 m each for the LB-Greater Beirut...

more
Issue 2009-07 Jinping/China

Jinping II: Gripper TBM for Hydro-Power Plant

At present the 2 power plant stages Jinping I and Jinping II are being constructed on the Yalong River, one of the main tributaries on the upper reaches of the Yangtze, in the Chinese province of...

more