On January 28, at the Xuyong beam fabrication yard of the Sichuan-Yunnan section of the Xubi Railway, 26 trial-produced T-beams were fully completed. On January 29, these T-beams underwent inspection by the Sichuan Provincial Quality Supervision Administration. After obtaining the certificate of conformity, the beam yard will commence mass production, laying the foundation for the launch of full-line bridge erection on April 1. Twenty kilometers away from the beam yard, the second lining concrete pouring is underway in the Yongfu Tunnel of the Xubi Railway. The tunnel was holed through on January 23 and is the tunnel project with the highest construction risk on the entire line... With breakthroughs in key control projects one after another, the construction of the Xubi Railway is progressing in an orderly manner toward the goal of completion in 2022.
　　Project Profile
　　Xubi Railway
　　Xubi Railway: Connecting the 'Dead-End' of Luzhou's Freight Railway
　　The Xuyong beam fabrication yard in the Sichuan-Yunnan section of the Xubi Railway is responsible for the prefabrication of 692 32-meter and 24-meter T-beams.
　　The Xubi Railway, namely the Xuyong-Bijie Railway, is a section of the Longchang-Huangtong Railway (from Longchang, Sichuan to Huangtong, Guizhou). The project starts from the existing Longfeng Station of the Na(Xi)-Xu(Yong) Railway in the north, enters Yunnan via Zhenxiong and Weixin, and then reaches Bijie, Guizhou, connecting with the Bi(Jie)-Zhi(Jin) Railway. It is an important component of the Longchang-Huangtong Railway, an auxiliary corridor for freight transport between the Sichuan-Chongqing region and the Beibu Gulf region. Once completed, it will eliminate the current 'dead-end' status of Luzhou's existing freight railway.
　　The Sichuan-Yunnan section of the Xubi Railway traverses remote areas along the Sichuan-Yunnan border, with a line length of 151.838 kilometers, an estimated total investment of 10.813 billion yuan, and a design speed of 120 km/h. It is a national Class I single-track electrified railway, positioned as a mixed passenger and freight line, with a construction period of 6 years.
　　Progress on the Front Line
　　Construction Proceeding Methodically
　　On January 27, the Lunar New Year was approaching. At the construction site of the Xuyong beam fabrication yard in the Sichuan-Yunnan section of the Xubi Railway, workers from various places remained at their posts, carrying out maintenance, formwork removal, rebar tying, mold welding... Construction proceeded methodically.
　　"To ensure the smooth passing of the beam yard certification, the beam yard strictly implements technical management measures, establishes a technical responsibility system, and practices dynamic management so that the entire production process is under control," said Zhao Lingrun, an on-site manager. The project department has established a quality assurance team and formulated a detailed quality inspection system to ensure that quality inspection has laws and rules to follow. Meanwhile, advanced equipment is used for bridge production, with key control over construction links such as raw material entry, formwork erection, concrete pouring, and tensioning, providing strong guarantees for prefabricated bridges and ensuring that every beam produced is a quality product.
　　The Xuyong beam fabrication yard in the Sichuan-Yunnan section of the Xubi Railway is responsible for the prefabrication of 692 32-meter and 24-meter T-beams for the Sichuan-Yunnan section of the Xubi Railway.
　　Thirty-Six Stratagems for Project Execution
　　Highest-Risk Tunnel Successfully Holed Through
　　On January 23, the Yongfu Tunnel, constructed under Contract Section 1 of the Xubi Railway, was successfully holed through, laying the foundation for the subsequent opening of the beam erection channel along the entire line.
　　The Yongfu Tunnel has a total length of 3,553 meters and traverses areas with complex geological structures and poor surrounding rock conditions. In addition, there are coal seam goafs along the route, and the construction site is located in remote mountainous areas with inconvenient transportation, difficult material transport, high construction difficulty, and high safety risks. Therefore, the tunnel is listed as a key control project on the entire line.
　　Since entering the tunnel for construction in December 2018, the project construction party has formulated construction plans tailored to local conditions: adopting simultaneous construction in two work areas, the inlet and outlet, and constructing with two excavation faces.
　　To ensure construction progress, the project construction party actively carried out technical research, using advanced geological prediction, monitoring and measurement, crown grouting with formwork, hot-melt welding and installation of waterproof boards, smooth blasting, and other technologies for construction, ultimately achieving high-precision, zero-deviation holing through of the Yongfu Tunnel. Currently, the construction party is pouring the second lining of the last section of the tunnel arch.
　　It is understood that most of the Sichuan-Yunnan section of the Xubi Railway is distributed within Xuyong County, and the entire Contract Section 1 has a total of 21 tunnels. As of now, 13 have been successfully holed through, and the excavation work of the remaining tunnels is over 96% complete.
　　Xubi Railway: Connecting the 'Dead-End' of Luzhou's Freight Railway
　　30-Story-High Slope Poured in Five Stages
　　The Sichuan-Yunnan section of the Xuyong-Bijie Railway advances from Xuyong toward Yunnan. The railway passes through a landscape of ravines and gullies, with a bridge-tunnel ratio as high as 89%. Apart from tunnels and bridges, both sides of the subgrade are also high mountains and cliffs. Entering the Gaofeng area of Xuyong, after passing through the Sunjiabang Tunnel, there is a 70-meter subgrade section. The subgrade is very short, but one side has a slope as high as 90 meters, equivalent to the height of a 30-story building. The slope has unfavorable geological phenomena such as fissures and rockfalls.
　　Wang Jialin, manager of the Fourth Sub-section of Contract Section 1 of the Xubi Railway, told reporters that the slope treatment method is blasting, flattening, and reinforcement, but a slope about 30 stories high obviously cannot be reinforced all at once, and the surrounding terrain conditions do not allow large-scale blasting. "Considering the slope location and surrounding environmental conditions, the high slope treatment plan is set as a five-stage reverse slope, with each stage 25-30 meters, and the slope surface reinforced with anchor cables and frame beams."
　　According to the slope treatment plan, the construction party adopts a layered excavation method from the surface downward. Combined with drilling construction machinery and the surrounding terrain, the first and second benches use controlled blasting schemes of deep-hole blasting and deep-hole weak loosening blasting in the main excavation area, and the upper 5 meters of the third bench use a controlled blasting scheme of shallow-hole weak loosening blasting. The remaining two slopes are excavated mechanically, finally forming a five-stage slope.
　　As of now, the largest high slope treatment project on the entire line has completed the blasting and excavation of the five-stage slope, and anchor rods and anchor cables are being installed. The slope frame pouring will be completed after the Spring Festival.