Capping of the Main Structure of Guanggang New Town Station on Guangzhou Metro Line 10 Completed Ahead of Time

Recently, a good news has spread again on Guanggang New Town Station for Guangzhou Metro Line 10 constructed by UCD’s rail construction company! With the completion of the last roof concrete pouring, the capping of the main structure of Guanggang New Town Station was completed successfully one week ahead of the scheduled node, winning good luck for the sprint stage of the subsequent construction in 2022. The Guanggang New Town Station is the third capped station on Guangzhou Metro Line 10, and is also the station with the largest single floor area on this route.

Guanggang New Town Station is the 13th station in the newly-built section of the Guangzhou Metro Line 10 project, connecting Dongsha Station in the east and Xilang Station in the west. Located in the southern industrial area of Guanggang New Town planned in Fangcun area, the east-west station lies at the intersection of two planned roads, north of Hejing Road.

The station is a two-story underground station with double islands and four lines, with a total length of 392 meters and the standard section as wide as 45.3 meters. With the foundation pit excavation depth reaching 18 meters or so, and a single-story building area coming to 18,000 square meters, the station ranks first among those on Guangzhou Metro Line 10. The deepest depth of the foundation pit reaching 33.15 meters places the sizable engineering volume in the second place among those on Guangzhou Metro Line 10.

Making plans scientifically to cripple influence of the high-tension cables

The north side of Guanggang New Town Station is close to 110kv and 220kv overhead high-tension cables, and the minimum clearance altitude under the high-tension cables is only 5 meters, making it impossible to conduct normal lifting operation under the existing conditions. Therefore, UCD scientifically optimized the construction scheme and, to skillfully avoid the high-tension cables, UCD specially adopted the reverse circulation drilling rig with lower height, and adopted the method of "inverted transportation in the pit with excavation at a single side" for earthwork in the foundation pit; In addition, considering that the lifting can only be made with the crane on the south side of the foundation pit, UCD chose the side wall opposite top support system for the lifting to conduct siding wall integral concreting, which substantially expedited. the construction progress and thus successfully completed the construction with the security of the high-voltage electric tower being ensured.

Overcoming difficulties in defiance of complex formation challenge

There were silt layers and fine sand layers in the foundation pit of the station, with the thickest reaching 12 meters, making it easy to cause deformation, water gushing and sand gushing in the foundation pit when excavation was conducted. Moreover, there were strongly weathered and moderately weathered silty mudstones in the base, with abundant fissures and large underground water, which posed great challenges to the excavation of the foundation pit of the station.

For this reason, UCD focused on innovation, tackling difficulties, and adopted the construction technology of long casing dry hole, which greatly accelerated the construction of retaining piles; After entering the stage of foundation pit excavation, the leakage of silty fine sand layer was found serious, threatening the safety of the foundation pit extremely. Through scientific planning and reasonable arrangement of working procedures, edge excavation was conducted to shorten the excavation interval, accelerate the speed of bolting and shotcreting and minimize the time for the exposure of soil between piles. At the same time, UCD specially set up an in-between pile plugging team, prepared enough emergency supplies, introduced an integrated drilling and injection machine, and grouted the leakage points the soonest. Moreover, through all-round monitoring and information management and control measures, the safety of the foundation pit and its surroundings was guaranteed with all effort,thus ensuring the smooth progress of the whole excavation process.

Racing against time and manifesting the graceful demeanour of UCD

Affected by a number of factors such as COVID-19, geological conditions, surrounding environment and environmental protection inspection, the construction of Guanggang New Town Station was interrupted, with effective operation time shortened, construction period tight and construction tasks arduous. UCD took measures actively, adjusted the personnel arrangement reasonably, exercised the responsibility system among sub-departments and districts, and strengthened the ability in project organization and management. In order to ensure that the construction has sufficient resources, the construction units increased manpower, material resources and machinery and equipment, adjusted the structure of the construction team in time, and strengthened the process control. The project department held regular production scheduling meetings every day to find problems and solve them in time. In addition, an incentive mechanism was also established to make the rewards and punishments clear. Teams with outstanding construction achievements were rewarded, and severe punishments were done against those incurring safety problems once they were found.

In the follow-up construction, UCD will continue to gather strength to work hard day and night and give full play to its own advantages to ensure the successful completion of the next-node targets.