On August 12, 2024, accompanied by the applause and cheers of all the builders, the main body pouring construction of the E1 pipe section—the last pipe section of the second batch of immersed tubes of the Ruyifang Radial Line System Project (Phase I)—was successfully completed, marking the full completion of the main body pouring work of the project's immersed tube tunnel and a key milestone in the project's construction.

Accelerating Progress: Tunnel Construction Progress Bar Refreshed Again

In the early morning of August 11, following the command "Start pouring," four concrete pump trucks started operating simultaneously, slowly injecting 1,665 cubic meters of concrete into the E1 pipe section weighing 30,000 tons. At the construction site, 30 concrete mixer trucks shuttled back and forth without interruption, and 70 construction workers stood at their posts, carrying out duties according to their respective task assignments. Thirty-five hours later, all pouring tasks were successfully completed.

As an important component of the project, the main line of the Ruyifang Tunnel Project is 1,511 m long, of which the immersed tube section in the river is 618 m long, consisting of 6 sections in total; the first batch of pipe sections was already immersed and joined last year. The sections poured this time are the second batch, divided into 3 sections, each 103 m long, 30.4 m wide, and 9.5 m high. With the completion of pouring for all second-batch immersed tubes, the project is one step closer to the goal of completion and opening to traffic.

Intelligent Construction: Building a Safe, Centennial-Quality Project

Concrete pouring is one of the core links in tunnel construction, and its quality directly affects the safety, durability, and service life of the project. To build a "leak-proof" immersed tube tunnel with high quality, the project team adopted the following measures: first, it used full-section concrete pouring technology, with the concrete structure poured in one step from the base slab to the top slab, effectively reducing longitudinal construction joints, which not only greatly lowers the risk of water leakage in the immersed tube but also effectively improves the quality of pipe section prefabrication and crack control performance; second, it introduced the currently largest full-section formwork trolley in China for immersed tube pipe section prefabrication and incorporated advanced technical means such as trolley stress and deformation monitoring and cooling circulating water during concrete pouring to ensure that the quality of immersed tube concrete meets requirements; third, it installed an intelligent temperature monitoring (wireless communication) system, enabling full-process management from temperature control standard formulation and temperature control measure tracking to temperature control status collection, temperature control analysis feedback, and dynamic management, thereby strengthening concrete crack control performance while ensuring construction progress, further improving the precision of concrete temperature control, and guaranteeing the pouring quality and centennial service life of the immersed tube.

Compacting Responsibilities: Weaving a Dense Safety Production Protection Net

Safety production is the lifeline of high-quality development. As an important water-related project, the Ruyifang Project's construction unit strictly implements the policy of "safety first, prevention foremost, comprehensive management," takes the implementation of "three managements, three responses, and three implementations" as the most effective measure, and adopts dynamic supervision and daily inspections to control and accept risk sources such as deep foundation pits, high slopes, and high formwork support on the site. Currently, during the critical flood control period of "late July to early August," in response to potential geological hazard risks of water-related projects, flood control and emergency drills were organized, fully simulating various foreseeable emergencies during the flood season, testing the rationality, scientificity, and practicality of emergency plans through actual practice, and improving the overall emergency rescue capabilities of project personnel. The project persists in strengthening personnel safety education, strictly conducting pre-shift education and technical briefings before daily operations, and ensuring all special operation personnel work with certificates. Since the project started, there has not been a single production safety accident, and the overall safety situation remains stable and controllable.

At present, the project has completed important engineering milestones such as the immersion and joining of the first batch of pipe sections. Next, efforts will focus on key processes such as leakage testing and floating of immersed tube pipe sections in the dry dock and construction of the immersed tube anti-anchor layer. The second batch of immersed tube immersion and joining construction is planned to be completed by the end of this year, and the project is expected to be completed and open to traffic in 2025.

Introduction to the Ruyifang Radial Line System Project (Phase I)

The Ruyifang Radial Line System Project (Phase I) is supervised by the Municipal Transport Bureau, organized and implemented by the Downtown Traffic Project Management Center, and constructed by China Railway Tunnel Group Co., Ltd. The project is located in Liwan District, Guangzhou, starting from the Ruyifang Interchange of the Inner Ring Road in the east, running southwest under the Pearl River, and connecting to Fangcun Avenue. It is an important channel enhancing the connection between Guangzhou's old urban area and Foshan's urban area and surrounding cities in the west. The project is about 2.4 km long in total. The main line of the tunnel project is 1,511 m long, including 893 m onshore and 618 m of immersed tube section, with six lanes in both directions; it is designed as an urban expressway, with a design speed of 40 km/h within the Huangsha-end loop area and 50 km/h elsewhere.

The project is one of the seven radial lines of Guangzhou's Inner Ring Road, an important component of Guangzhou's expressway network skeleton, and an important entrance and exit in the southwest direction of Guangzhou. It distributes traffic from the Inner Ring Road and Guangzhou's central urban area toward the southwest, effectively enhancing the connection between Guangzhou's old urban area and Foshan's urban area and surrounding cities in the west, greatly promoting the prosperity and development of industry, agriculture, and commerce in the Fangcun area, and is of great significance to the economic development of the Bai'etan Economic Circle, Huadiwan, the flower production base, and the Dongsha Economic Development Zone, as well as the prosperity of riverside warehousing.

After the project is completed and opened, the travel distance between the Inner Ring Ruyifang Interchange and Fangcun Avenue will be greatly shortened, and travel time will be reduced from the original 15–30 minutes to 4 minutes, greatly improving traffic efficiency on both sides of the Pearl River.

Project Construction Timeline

July 18, 2018: Project commencement mobilization meeting held;

January 17, 2019: Construction began on dredging of the temporary waterway;

December 24, 2019: Enclosure structure of the onshore tunnel at the Fangcun end completed;

May 11, 2020: Three deep foundation pits—the Huangsha-end dry dock deep foundation pit, the Fangcun-end onshore tunnel deep foundation pit, and the Fangcun-end revetment deep foundation pit—successively completed enclosure structure construction within one month, and deep foundation pit excavation began;

August 20, 2021: Concrete pouring for E5-1, the first immersed tube section of the first batch, completed;

June 6, 2022: Pouring of the last pipe section of the first batch of immersed tubes completed;

August 6, 2022: Pouring of the short pipe section of the first batch of immersed tubes completed;

October 3, 2022: Demolition of the steel sheet pile cofferdam at the Fangcun end began;

November 10, 2022: Installation of ballast water tanks for the first batch of immersed tubes completed;

November 16, 2022: Installation of steel end bulkheads for the first batch of immersed tubes completed;

November 18, 2022: External waterproofing coating for the first batch of immersed tubes completed;

November 22, 2022: Water refilling of the dry dock for leakage testing of the first batch of pipe sections carried out;

March 15, 2023: Phase I of steel pipe pile extraction for the dry dock cofferdam successfully completed;

May 6, 2023: Steel dock gate of the first batch of immersed tubes opened, connecting the dry dock with the Pearl River;

June 26, 2023: The first immersed tube section E6 floated out of the dock;

October 31, 2023: Floating transport and installation of the first batch of immersed tubes completed;

May 12, 2024: Caissons for the Fangcun revetment officially entered the lifting stage, marking the orderly progress of revetment restoration construction and providing basic conditions for the next step of revetment parapet wall construction;

July 2024: Pouring of the first pipe section of the second batch of immersed tubes completed;

August 2024: Main body pouring work of the immersed tube tunnel officially concluded.