The Central Yunnan Water diversion Project is a landmark project among 172 major water-saving water conservancy projects determined by The State Council. It is also the largest water resource allocation project with the largest scale and the largest investment in southwest China, and one of the largest water diversion projects under construction in China. The "Yunling" TBM put into use this time is the largest open-type TBM in the world at present. It is a "sharp tool" tailored for the construction of three standard Xianglu Mountain tunnels in Dali Section of the Yunnan-Central Water diversion project undertaken by China Railway Tunnel Bureau. Xianglushan Tunnel is the key throat control section of the whole central Yunnan water diversion project. The total length of the tunnel is about 62.596 km. The construction of the tunnel is confronted with such technical problems as karst cave, crushing, water gushing and mud outburst, large hardening of soft rock, large active fracture, rock burst and high seismic intensity zone.
In order to predict the geological structure ahead of TBM excavation in real time, the YSD-3 seismic advance detection system independently developed by CCTEG Xi 'an Research Institute (Group) Co., Ltd. carried out a 3-month field test in the project department. Relevant leaders of Southwest Region and Geophysical Research and Development Center of Geophysical Prospecting Instrument Institute participated in the whole experiment.
The experimental results of TBM tunnel advance detection and prediction show that the system runs stably and reliably with high signal-to-noise ratio, and the imaging and prediction results are in good agreement with the actual situation. The success of the experiment indicates that the seismic advance detection system with excavation is not only suitable for real-time advance geological prediction of roadway excavation in underground coal mine, but also has a promising application prospect in non-coal fields.