On December 11, the Huangmaohai Cross-Sea Link, invested in and constructed by Guangdong Communications Group Co., Ltd. and participated in by CCCC Road & Bridge Construction Co., Ltd., was completed and opened to traffic, shortening the drive from Zhuhai to Jiangmen from more than one hour to about 30 minutes.
The Huangmaohai Cross-Sea Link is the third important cross-sea link in the Guangdong-Hong Kong-Macao Greater Bay Area. The project is about 31 kilometers long, built to a two-way, six-lane expressway standard with a design speed of 100 kilometers per hour. Contract section T3, in which CCCC Road & Bridge participated, has a route length of about 4.05 kilometers and mainly includes the east tower, east auxiliary pier and east transition pier of the Gaolan Port Bridge and the hoisting of the east-side steel box girders; the foundation, substructure and 40-meter cast-in-place girders of the east approach bridge; the interchange mainline bridge; ramps A, B, E and F and the subgrade; and the transport and erection of small box girders and ancillary works within the stake-number range. The controlling works, the Gaolan Port Bridge, is a single-pylon, double-cable-plane fully floating cable-stayed bridge with a main span of 700 meters.
The CCCC Road & Bridge project team has always adhered to craftsmanship and meticulous construction. It has successively applied large-diameter, over-100-meter bored piles in marine silt geology; a prefabrication process of horizontally assembled reinforcement for variable-cross-section pier shafts; concrete crack control in windy marine environments; and integral hoisting technology for large-segment reinforcement of spatial curved surfaces. These have effectively reduced construction safety risks and effectively improved construction efficiency and quality, creating the "Huangmaohai speed" of one tower column segment every five days. The formwork control precision of the waist-shaped single-column tower has carved the "small waist" shape that is solid inside and beautiful outside.
Innovative pile foundation construction technology overcomes geological construction challenges in sea areas
The main pier foundation of the Gaolan Port Bridge adopts a group pile structure, with a total of 31 super-large-diameter bored cast-in-place piles of 3 meters in diameter and a maximum hole depth of 120 meters, making it a veritable "giant" in offshore construction of large-diameter, ultra-long foundation piles. However, the geological conditions in the Huangmaohai sea area are extremely complex, with thick silt layers and fractured rock strata, making drilling extremely difficult. Traditional pile foundation construction techniques can hardly guarantee construction quality and progress under such complex geological conditions.
The CCCC Road & Bridge project team rose to the challenge, conducted an in-depth analysis of the geological characteristics of the sea area, innovatively adopted the construction method of large-diameter rotary drilling rigs, and independently developed a complete set of offshore ultra-deep pile foundation construction technology. Through precise measurement and control of drilling parameters, the pile verticality deviation was controlled within 0.6%; mud performance was optimized; and hole wall stability was monitored in real time to prevent hole collapse and deviation, enabling all 51 piles to meet Class I pile standards.
Integral reinforcement hoisting technology cleverly builds the spatial curved-surface cable tower "small waist"
The cable tower of the Gaolan Port Bridge is a single-column tower with a total height of 254.7 meters. The tower column cross-section gradually changes from circular to round-ended and then from round-ended back to circular, and is known as the offshore "small waist." The maximum diameter of the tower column is 18 meters and the minimum diameter is 8.5 meters. The spatial shape of each segment of the main tower changes continuously, resulting in different required formwork shapes. Shaping the special-shaped tower with spatial curved surfaces is difficult and the construction process is complicated.
During the construction of the main tower, the CCCC Road & Bridge project team overcame the problem of short effective working time at height caused by frequent strong winds, broke through conventional technical barriers, and innovated processes and methods to hoist the reinforcement of the spatial curved-surface single-column tower in a complete segment with "one hook" and achieve millimeter-level precise docking at height, creating the "Huangmaohai speed" at which the Huangmaohai cable tower grows segment by segment. The project team carried out technical research on formwork for the curved-surface cable tower, conducted digital management of the entire life cycle of the cable tower, and formed a reusable "shaping box" formwork technology based on the combination of BIM and CNC fine carving technology, achieving high-precision fitting of the cable tower formwork.
Intelligent temperature control and crack prevention technology safeguards high-quality concrete pouring
In a typhoon-prone marine environment, mass concrete is prone to excessive temperature differences between the inside and outside due to heat of hydration, leading to cracks and affecting structural durability. Taking the main pier cap of 35 meters × 45 meters × 6 meters as an example, the adiabatic temperature rise generated by 8,000 cubic meters of concrete during pouring would cause the cap to crack from the inside out. This is not merely a question of whether the appearance is beautiful; it concerns the durability of the cap and engineering safety.
To this end, the CCCC Road & Bridge project team established a special task force, conducted in-depth research on concrete temperature control technology, and developed an active temperature control system for mass concrete. By adding ice cubes and using spray cooling during mixing, using low-heat-of-hydration cement, and optimizing the concrete mix proportion, the placing temperature was reduced from the source, and temperature sensors were embedded inside the cap to monitor changes in the internal temperature of the concrete in real time.
Based on the back-end temperature data of the intelligent control system, the cooling water circulation system is automatically adjusted to precisely control the internal temperature of the concrete between 63°C and 65°C, far better than the national indicator of 70°C. The team's research achievement, the "Active Temperature Control System for Mass Concrete Based on Cloud Monitoring," also won the Gold Award at the 3rd China Highway Association Micro-Innovation Competition in 2022. In addition, during concrete pouring, new materials such as anti-cracking fibers and anti-cracking agents were added to the concrete, combined with curing measures, achieving good anti-cracking and curing results. These multiple measures also achieved high-quality construction of each main tower segment.
The Gaolan Port Bridge project of the Huangmaohai Cross-Sea Link is an important part of the ninth horizontal line—Hong Kong, Macao to Taishan (the Hong Kong-Zhuhai-Macao Bridge and its connecting lines + the Hongwan to Gaolan Port Expressway + the Cross-Huangmaohai Link (long term))—of the regional expressway network planned and constructed by the three cities of Zhuhai, Zhongshan and Jiangmen under the "ten horizontals, fourteen verticals and fifteen additional lines" framework. After the project opens to traffic, it is of great significance for implementing the cooperative spirit of the Guangdong-Hong Kong-Macao Greater Bay Area, strengthening connections within the Greater Bay Area, optimizing the regional expressway network, changing the current situation of a single river-crossing link, effectively promoting the clustering of the equipment manufacturing base in western Pearl River, and further strengthening the coordinated development of the Hengqin Free Trade Zone, Gaolan Port and the Daguang Bay Economic Zone.
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