The shield tunneling construction of the Sixth Engineering (Xiamen) Co., Ltd. of CCCC Third Harbor Engineering Co., Ltd.'s Xiamen Metro Line 6 Sunjia section successfully navigated through a tricky "final hurdle".
The area around the right-line shield launching shaft for this project is densely populated with buildings, and the lifting shaft for the shield machine had already been sealed. Conventional lifting plans were impossible to implement. Facing this dilemma, the project team adapted to the challenge and innovatively adopted the "Shield Machine Translation and Reception Method," enabling the shield machine to achieve a "lateral breakthrough" underground, precisely translating it to the left-line shield shaft for disassembly and lifting.
The successful implementation of this plan relied on the team's collaborative efforts and rigorous control. Party member Su Zhaohu, in particular, stayed on-site for several consecutive nights. As the "equipment steward," he meticulously implemented safety regulations and guarded every construction milestone.
Rewind to 12 days ago. According to the original plan, after the shield machine completed the right-line drive, a large crane would be needed, extending its "long arm" to lift the main machine and rear auxiliary equipment out of the shaft one by one for transport and removal. However, due to earlier traffic diversion work during construction, the right-line lifting shaft had been sealed in advance, effectively closing off the shield machine's original lifting channel.
The project department worked overnight to formulate a new plan: the right-line shaft would serve as the receiving station. A reception frame would be installed at the shaft bottom, with translation tracks laid underneath. The shield machine would first "climb" from the right-line tunnel onto the reception frame. After the rear auxiliary equipment was disassembled, it would then "translate" along the tracks to the left-line lifting point for hoisting.
Su Zhaohu received the task just as he finished his night shift handover. He stepped away from the shield machine, the smell of engine oil still on his hands, faint traces of red in his eyes. With 12 years of Party membership and 10 years of experience in metro equipment management, he understood the risks of this new plan better than anyone.
The shield machine cutterhead plus the shield body weigh 300 tons in total, equivalent to over 200 cars. The flatness error of the translation tracks had to be controlled within 3 millimeters, and the load-bearing capacity of the reception frame couldn't be off by even a bit. Any oversight could lead to translation failure or even trigger a safety incident.
To ensure precision, Su Zhaohu took the lead in establishing a "three-level inspection system" and "planted" himself on-site. When the track steel materials arrived, he squatted in the storage yard, inspecting each piece one by one. His fingers, along with tape measures and calipers, glided over the steel surfaces, carefully checking for surface defects and dimensional deviations. No dent exceeding the allowable standard escaped his notice. During track welding operations, he stayed by the underground workface throughout. The moment the welding torch stopped, he immediately set up the level to recheck the elevation and smoothness of the weld seams. He often said, "Being off by even a little affects subsequent work. We must keep precision in check."
Just then, Xiamen encountered the rainy season. Continuous rainfall made the shaft wet and slippery. "We can't let the rain delay progress," Su Zhaohu said. He coordinated overnight to get anti-slip mats and laid them throughout the construction area. To seize construction windows between rains, he led the equipment team, working over ten hours non-stop. Sometimes, when he was so tired his eyelids felt heavy, he would take a short break in the designated rest area to recover. Upon waking, he would quickly rub his fingers to adjust his focus, pull out his tape measure and calipers again, and continue calibrating the steel rails.
When the last section of track was welded and all errors were confirmed to be within standard, he finally noticed his work clothes were soaked through with rain and sweat, and a thin scab had formed over a cut on the back of his hand from the rail edge. "Brother Su always says that equipment is the 'legs' of construction. If the legs aren't steady, the work can't be done well," recalled young technician Xiao Liu, his eyes full of admiration as he remembered the scene.
The shield machine successfully "climbed" onto the reception frame. The subsequent translation was even more critical. The project team needed to disassemble the screw conveyor, segment erector, and other rear auxiliary equipment inside the tunnel. Then, using two 100-ton clamping cylinders to secure the track, they would synchronously extend the cylinders via the pump station to push the reception frame, moving the main machine along.
However, during the first pushing test, the instrument panel suddenly flashed red – the main machine had deviated by 3 centimeters. "Stop!" Su Zhaohu shouted. Everyone's hearts leaped into their throats. "Pushing further could derail the equipment. If the seals get damaged, subsequent repairs would delay us for at least half a month," he said gravely.
Technicians suggested increasing the number of pushing cylinders. But Su Zhaohu shook his head: "More cylinders can easily lead to uneven force distribution. That treats the symptom, not the root cause. We need to check the contact between the track and the reception frame first." With that, he crawled underneath the reception frame, inspecting the contact points between the frame and the tracks one by one. He finally identified the problem: two points on the reception frame had experienced minor settlement, causing the force distribution to shift. He immediately coordinated materials and led the team in welding steel plates to reinforce the reception frame again.
During the second pushing attempt, Su Zhaohu stood by the control panel, eyes fixed on the real-time monitoring data, fingers tightly gripping the control lever, holding his breath with every adjustment of the cylinder pressure. He repeatedly ran to the side of the track, squatting down to check the positional deviation. 2 meters, 1 meter... Only when the main machine came to a steady stop directly beneath the left-line lifting shaft did he finally relax. The lights in the shaft shone on his dust-covered work clothes. He rubbed his aching shoulders, which were almost too sore to lift, and breathed a sigh of relief. The 17.1-meter translation was finally completed without the slightest error.
The application of this translation and reception method delivered excellent results in both "economic and social" aspects, receiving high recognition from the project owner. Behind this successful "lateral breakthrough" of the shield machine lay Su Zhaohu's meticulousness in "looking for bones in an egg," as well as the seamless collaboration and pursuit of excellence of the entire project team. (Content provided by Guo Longji)
Company:The Sixth Engineering (Xiamen) Co., Ltd. of CCCC Third Harbor Engineering Co., Ltd.
Contact Person:lugang
Contact Person:lugang
Website: www.ccshj6.com
City:Xiamen, Fujian
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