Sprint to the Fourth Quarter, Win the Final Battle

On October 22, the No.1 Sub-branch of Guangxi Road Construction Group's Hezhou-Bama Expressway (Xiangzhou-Lai bin Section) Project ("Xianglai No.1 Sub-branch") completed the concrete pouring of the last pile foundation for the Peisen Liujiang Grand Bridge, marking the successful completion of all 378 pile foundation pours for the entire bridge. Zoomlion's full-slewing rigs once again achieved outstanding results.

The Peisen Liujiang Grand Bridge is located in Xiangzhou County, Laibin City, and is a key control project of the Hezhou-Bama Expressway (Xiangzhou-Lai bin Section) in Guangxi. The bridge is 2,580 m long, with a main span of 280 m, making it the world's longest-span highway prestressed concrete partial cable-stayed bridge currently under construction.

New Craftsman Workshop — Building "One Highland and Four Centers"

The pile foundations of the Peisen Liujiang Grand Bridge are large in diameter (2.5 m) and numerous. The pile locations are covered by thick layers of cobble and boulder deposits, with highly developed karst features. The karst caves overlap and interconnect, with a single cave chamber reaching up to 25 m, a complex karst condition rarely seen in the history of bridge construction in China. During the construction of the 24 pile foundations for the P2 main pier on the Xiangzhou bank, 105 caves of various sizes were encountered, with the deepest pile reaching 87.3 m and an average of 4.4 caves per pile. In the early stage of pile foundation construction, conventional impact drills, rotary drilling rigs, and techniques could not ensure successful hole formation, affecting the progress of pile foundation construction.

Aerial view of the Peisen Liujiang Grand Bridge in the early construction stage  Photo by Huang Jingji

To overcome the project's difficulties, Guangxi Road Construction Group set up the "New Craftsman Workshop" beside the Peisen Liujiang Grand Bridge. Relying on this science and technology brand, it built "One Highland and Four Centers": a talent cultivation highland, a science and technology innovation center, a construction monitoring center, a BIM technology center, and an intelligent and informatization center, and carried out research on the "10 Key Technologies" for the Peisen Liujiang Grand Bridge.

The "BIM + seismic wave CT + intelligent multifunctional geological drilling rig" precise pile foundation geological judgment technology is one of the key technologies applied in the bridge's pile foundation construction. Through advanced forecasting and drilling of geological data and materials, BIM technology is used to input data and relevant geological materials, simulate and analyze geological conditions, and generate detailed 3D geological maps. This accurately determines the types and distribution of karst and fillings at the main pier locations, effectively avoiding hazards and improving the safety of pile foundation construction.

Construction site of the Peisen Liujiang Grand Bridge  Photo by Liu Yunyan

The full-casing full-slewing drilling rig construction technology for large-diameter and deep pile foundations under "thick, highly permeable, loose overburden + deep complex karst" geological conditions is another key technology applied in the bridge's pile foundation construction. Guangxi Road Construction Group introduced the first Zoomlion 260 full-casing full-slewing drilling rig in Guangxi's transportation industry. This equipment has the advantages of strong adaptability, high efficiency, safety, reliability, high hole-forming accuracy, and no mud pollution. It is suitable for bridge pile foundation construction in various complex and unstable geological conditions, such as cobble and boulder strata, karst strata, thick quicksand strata, high backfill strata, and swamps. It successfully solved common problems in the pile foundation construction of the Peisen Liujiang Grand Bridge in karst-developed geology, such as hole collapse, hole deviation, and steel casing deformation. The average hole-forming speed per pile foundation was 2 days faster than traditional pile foundation construction techniques, effectively ensuring the quality of pile foundation construction.

Deputy Chief Engineer of the project Huang Jianxi is one of the four graduate students assigned to the project. "When I first arrived at the project, it was the most difficult time for the pile foundation construction of the Peisen Liujiang Grand Bridge. We went through an exploration period full of difficulties. In this process, our team not only accumulated experience in the practical application of multiple bridge technologies but also improved our problem-solving abilities and management level."

Racing Against the Clock — A Battle Against the Flood Season

The construction of the main piers of the Peisen Liujiang Grand Bridge is greatly affected by seasonal water levels. Whether the main piers could be built above water before the flood season became a key milestone for the completion of the bridge. "At that time, it was really like fighting a war. As soon as the flood came, we had to evacuate first." Recalling the period of racing against the flood season, Liao Yiqiang, Deputy Project Manager of the Xianglai No.1 Sub-branch, was deeply impressed.

Flood at the Peisen Liujiang Grand Bridge  Photo by Huang Jingji

The P2 main pier on the Xiangzhou bank and the P3 main pier on the Laibin bank are located in the Liujiang River channel. The two water-crossing piers have a total of 48 pile foundations, which are 2.5 m large-diameter group piles underwater, with the highest water level during the flood season reaching 69 m.

To win this race against the flood, the project set up the Xiangzhou bank and Laibin bank work areas on both sides of the Peisen Liujiang Grand Bridge, each equipped with a complete set of standard stations to support the construction of the main bridges and approach bridges on both banks. Work was carried out 24 hours a day without interruption, and the construction organization was continuously adjusted according to actual conditions, with construction plans optimized, while efficiently advancing construction on both the Xiangzhou and Laibin banks.

Construction site of the Peisen Liujiang Grand Bridge  Photo by Liu Yunyan

In the pile foundation construction of the main pier on the Laibin bank, the project completed the construction of 24 large-diameter pile foundations on the Laibin bank in May 2020 at an average speed of one main pier pile foundation every 3.5 days, 9 days ahead of the original construction plan, and moved on to the mass concrete pile cap construction stage. In this thrilling contest with the flood, the road builders persevered and finally raised the banner of victory.

Road Construction Red Heart Knot — Gathering the Greatest Synergy for Breakthroughs Through Party Building

With the "Road Construction Red Heart Knot" Party building brand as its core, the project Party branch built a dense "red network," maximizing the role of the Party branch as a fighting fortress and the exemplary vanguard role of Party members, gathering red strength, letting the Party flag fly high on the front line, and making Party building a source of driving force.

Party members and young employees of the Xianglai No.1 Sub-branch at the pile foundation construction site  Photo by Lu Zhonghua

The Party Member Vanguard Team of the Xianglai No.1 Sub-branch advancing the construction of the Peisen Liujiang Grand Bridge  Photo by Huang Jingji

Project Party member Wu Zuxi staying at his post during the Spring Festival  Photo by Huang Jingji

The project established the Peisen Liujiang Grand Bridge Party Member Vanguard Team, designated Party member vanguard posts and demonstration areas, and focused on overcoming various difficulties during construction. During the Spring Festival, the Party Member Vanguard Team voluntarily stayed on the construction site and worked on the main pier pile foundation construction with the attitude of "no break for the Spring Festival." During the severe period of the epidemic, the Party Member Vanguard Team charged to the front and strictly implemented every epidemic prevention and control measure. When pile foundation construction was seriously hindered, the Party Member Vanguard Team did not wait or rely on others, promptly adjusted the construction plan, and efficiently and safely advanced the pile foundation construction progress. During the construction of the grand bridge, the project Party branch carried out paired co-building activities with local governments, owners, and supervision units, actively leveraging the role of co-building units and gathering the greatest synergy for project breakthroughs.