Introduction of Pearl River Tunnel?

Pearl River Tunnel is located in Liwan District, Guangzhou City, Guangdong Province, China. Construction started on June 1990, and was completed and opened to traffic on February 28th 14, with a total investment of 600 million RMB, which was mainly undertaken by Guangzhou Zhujiang Tunnel Industry Co., Ltd., with a total length of 1238.5 meters and a middle section of 475 meters, showing a north-south trend. The entrance and exit at the northern end of the tunnel is located in Huangsha, Liwan District, connecting the inner ring and 623 Road, and the entrance and exit at the southern end is located in Fangshang Village. Connecting Huadi Avenue is a river-crossing tunnel across the Pearl River, and it is the first large-scale underwater tunnel designed and constructed by immersed tube method in Chinese mainland.

Tectonic layout

The tunnel has three pipes and three holes, two holes on the west side are two-lane automobile pipes, and the first pipe on the east side is designed as the double-track pipe of Metro 1 Line, which consists of three parts: Huangsha section on the north bank, middle section of the river and Fangcun section on the south bank. Before the subway was built, it was intended to be used as a bicycle tunnel, but the subway started immediately after the tunnel was completed, and there was a toll plaza at the south entrance. Since Guangzhou has implemented the annual car ticket system, cars in this city do not need to pay by parking tickets, so the toll plaza is basically.

Construction method

Guangzhou Salvage Bureau of the Ministry of Communications undertakes the underwater part of the tunnel, which is 320 meters long. The immersed tube method is used for construction, which is divided into five sections: prefabrication and sinking. Immersed pipes are connected end to end and finally to the shore, which can connect the whole tunnel. The construction period is 18 months.

According to the characteristics of the project, Guangzhou Salvage Bureau of the Ministry of Communications adopts the on-board prefabrication scheme, which is called "mobile dry dock" in the industry. Specifically, pipe joints are prefabricated on the barge named "Heavy 160 1", and then towed to the tunnel by tugboat for sinking and installing the platform.

"Mobile dry dock" technology is an advanced technology in tunnel construction, which can make the tunnel buried shallower, occupy less land and save engineering investment. It solves the limitations of traditional schemes such as high cost and limited space.

It is the first three-hole tunnel built by advanced immersed tube technology in China (two holes are vehicle tunnels and one hole is subway passage), and it is also the only vehicle tunnel crossing the Pearl River in Guangzhou at present. The tunnel is 1380m long, 33.4m wide, 457m long and 8 15m high, with a total investment of 680 million yuan.

The floating, transportation and sinking of pipe joints should be carried out at low tide to avoid the influence of large flow velocity. This project adopts the immersed tube method of large crane, and the main steps of installing immersed tube are as follows:

1. Lift the prefabricated pipe joint from the dry dock and drag it to the sinking position.

2. Inject water into the pipeline to bear the cabin, so as to counteract the buoyancy of the river, and make the pipeline joint sink into the dug riverbed groove at the predetermined position. (No.1-4 pipe joint has a negative buoyancy of 200-300 tons, and No.5 pipe joint has a negative buoyancy of 50 tons, from Huangsha shore to Fangcun shore. )

3. Pull the pipe joint with the pipe joint in place in the previous section, so that the GINA rubber pad is placed between the two pipe joints to form an effective initial watertight ring.

4. Pump the water between the end seals of the two pipe joints to form a vacuum state, so that the surrounding river water can tightly press the Gina rubber pad, and the joint can reach the required firm watertight ring.

5. Dismantle the end seals on both sides of the joint, and install Ω sealing ring inside the joint as the second water stop line.

6. Fill the ballast tank with water1400-1500t, and adjust it with four vertical jacks. Make the gap between the bottom of the pipe and the groove of the base 600 mm

7. Fill the medium and coarse sand with sand flow method, and treat the foundation at the bottom of the pipe, so that the tunnel structure is evenly supported on a foundation surface.

8. Remove the vertical jack, leaving four pillars.

Finally, the immersed tube is covered with a layer of gravel to protect the pipeline.

The key of this immersed tube section is rubber pad. The rubber pad is a Gina rubber pad imported from the Netherlands, which was originally 230 mm thick. After water pressure docking, it is only 90mm thick, forming a very strong watertight ring, which ensures the sealing safety of the river-crossing tunnel.

Convenient transportation

After the opening of the Pearl River Tunnel, Fangcun no longer needs to rely on the Pearl River Bridge for external traffic, and even replaces the Pearl River Bridge as the main traffic trunk road leading to Foshan and the South China Sea. As the Pearl River Tunnel has become the traffic artery leading to Foshan and the South China Sea, many vehicles are used every day, and the traffic volume has surged from 55,000 vehicles per day to 65,438+10,000 vehicles per day, far exceeding the design capacity of the Pearl River Tunnel, resulting in extremely busy traffic. Therefore, the government is studying the construction of Zhoutouzui Tunnel and Ruyifang Bridge to ease the traffic pressure of the Pearl River Tunnel.

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