A Steel Dragon Crossing Mountains and Rivers - Inventory of Key and Difficult Projects of Yawan High Speed Railway

Original Title: Steel Dragon Crossing Mountains and Rivers - Inventory of Key and Difficult Projects of Yawan High Speed RailwayThe Yawan High Speed Railway, which connects Jakarta, the capital of Indonesia, with Bandung, the capital of West Java Province, officially opened on the 2nd. This "steel giant dragon" that travels through mountains and rivers on Java Island has once again polished the golden business card of "China's high-speed rail"

Original Title: Steel Dragon Crossing Mountains and Rivers - Inventory of Key and Difficult Projects of Yawan High Speed Railway

The Yawan High Speed Railway, which connects Jakarta, the capital of Indonesia, with Bandung, the capital of West Java Province, officially opened on the 2nd. This "steel giant dragon" that travels through mountains and rivers on Java Island has once again polished the golden business card of "China's high-speed rail".

The Yawan high-speed railway has a total of 13 tunnels and 56 bridges, with a bridge tunnel ratio of 76%. There are a total of 26 controlled and difficult projects along the entire line, including continuous beams, steel truss beams, tunnels, subgrades, stations, high-speed train stations, etc. The builders of China and Indonesia bravely overcome difficulties and together complete tasks with high standards and quality.

Innovative construction methods for tunneling

The volcanic geology along the Yawan high-speed railway is prominent. Prior to construction, survey and design have been carried out to avoid unfavorable geology to the maximum extent possible. However, the soft soil and high water content surrounding rock still bring many troubles to tunnel construction.

Tunnel 10, located in the suburbs of Bandung City, is the tunnel with the highest construction risk along the entire line. The tunnel passes through an existing operating railway with a curve radius of only 200 meters below the entrance section, and construction can easily cause settlement of the existing railway roadbed.

Several Chinese experts have developed a special design plan based on on-site research, using various construction methods such as vertical and horizontal beam lifting reinforcement, double layer large pipe shed, etc. to overcome difficulties such as weak surrounding rock and high water content, and effectively control the settlement of existing railways. "Guo Yupeng, the chief engineer of the bridge and tunnel work area of the Yawan Project Department of China Railway Third Bureau, responsible for construction, said.

Indonesian Minister of Transport, Budi Karya Sumadi, stated that the professional skills, execution, and dedication demonstrated by Chinese builders during the construction of the Yawan high-speed railway are worth learning from the Indonesian side.

The No. 2 tunnel, with a total length of 1052 meters and a maximum burial depth of 53.6 meters, is the most difficult tunnel to construct on the southwest side of Puwagada County, West Java Province. The tunnel body is mainly composed of expansive mudstone, which weakens quickly when encountering water and is prone to collapse during excavation.

When repairing the tunnel, the workers from both countries worked in three shifts and worked day and night continuously. The determination of Chinese colleagues to do their best to overcome difficulties was very touching, "said Hendry Fernanda, the construction site safety officer.

Zhou Chaode, the project manager of China Electric Power Construction and Hydroelectric Seventh Bureau, who is responsible for construction, introduced that more than 60 backbone tunnel and grouting professionals have adopted the method of surface grouting and steel pipe piles to reinforce the ground according to local conditions. Special construction methods such as double-sided wall construction inside the tunnel have effectively controlled settlement deformation and ensured the safe and smooth progress of tunnel construction.

Overcoming External Interference and Erecting Box Girders

The total length of the bridges on the Yawan high-speed railway is 88 kilometers, which requires crossing rivers, highways, or existing railways. The complex external spatial relationships have posed many challenges to the installation of box girders.

The Yawan High Speed Railway No. 2 Grand Bridge has a total length of 36 kilometers and is adjacent to the Jakarta Bandung Expressway, with 24 continuous beams installed. Among them, the DK9 continuous beam spans a 3-story highway ramp, and the closest distance between the main pier and the highway ramp is only 20 centimeters. The construction space is narrow, making it the most complex and difficult control project for the entire construction environment and the most affected by external interference.

Jiang Hongyan, the project manager of China Electric Power Construction Eighth Bureau, who is responsible for construction, told reporters that under the leadership of China Railway Group International Company, the project department has invested a large amount of resources to ensure the simultaneous construction of multiple continuous beams. Through linear monitoring technology cooperation with Central South University, it ensures the smooth closure of the continuous beam group.

Behind the big project is the Indonesian employees who are adding bricks and tiles. The project department responsible for offline projects such as bridge, roadbed, and track slab laying prioritizes nearby villagers in terms of working hours, and organizes training on welding, mud tiles, and lifting to help them quickly grasp work standards and quality requirements.

Suti is about 43 years old and came to work in the project department 5 years ago. After coming to the project department, my salary has increased by nearly 30%. More importantly, after training, I have mastered professional forklift operation skills, so I won't be afraid of not finding a good job in the future, "he said.

The box girder erected on the DK1114 bridge from Bandung to Jakarta is the only cross existing railway box girder erection project along the entire line. For the construction team in China and Indonesia, erecting a single 32.6 meter long and 700 ton box girder on an old railway that has many trains coming and going every day is a huge test.

The task of my teammates and I is to make accurate statistics on the information of passing trains, with the start and end times accurate to seconds. If there are any discrepancies, it will directly affect construction safety, "said Villa, the safety officer of No. 4 beam yard.

Based on the information collected on site, the construction unit selected two time periods without trains passing through late at night for construction. After the last train in the evening, various large mechanical equipment such as Chinese made beam lifting machines and tunnel transportation equipment quickly entered the site.

Although the construction time was tight, the pace was not chaotic, and the beams were erected well and quickly according to the plan. If it weren't for personal experience, it would be difficult to imagine how this challenging project could be completed, "Villa said. After three consecutive days and nights of hard work, the erection of the box girder across the existing railway was successfully completed.

China's mechanical equipment "showcases its skills"

During the construction of the Yawan high-speed railway, it is not difficult to see the presence of large-scale mechanical equipment, which has made great contributions to safe and efficient construction from China.

The Yawan High Speed Railway Tunnel 1, with a total length of 1885 meters and a maximum burial depth of 34 meters, is currently the largest railway shield tunnel in Southeast Asia. During the construction of Tunnel 1, a super large diameter shield tunneling machine independently developed and manufactured by China Communications Tianhe Mechanical Equipment Manufacturing Co., Ltd. from Suzhou, Jiangsu was used, with an excavation diameter of 13.23 meters. Tunnel 1 crosses under construction light rail, highways, and densely populated areas with two mosques on its side. It is rich in groundwater and surface water, and the tunnel passes through unstable volcanic deposits. The construction conditions are complex, requiring high performance requirements for shield tunneling machines that pass through the underground.

Lu Xiaomin, the project manager of CCCC Tianhe Yawan High Speed Railway, told reporters that the shield tunneling machine adopts the world's advanced mud water layered reverse washing circulation technology, which can effectively cope with construction risks. The shield tunneling machine excavated a total of 1469 meters in Tunnel 1, and the actual maximum wear of the cutting tools was only 35 millimeters, achieving ultra long distance excavation without changing the cutting tools, further reducing the safety risks brought by changing the cutting tools.

The high-speed train depot located in Bandung is a maintenance and renovation base for high-speed trains, and is also one of the key and difficult projects for the entire Yawan high-speed railway line.

The area where the high-speed train is located has a soft soil foundation with a depth of 22 to 25 meters, which is volcanic ash sedimentary soft soil with low bearing capacity and is not conducive to the stability of the upper structure. Therefore, the foundation treatment has caused some trouble. "Zhu Chengquan, Chief Engineer of the Dekarur Station Project Department of China Railway Fourth Engineering Group, told reporters that plastic drainage board insertion machines transported from China to Indonesia have come in handy. This equipment not only has high construction efficiency but also relatively low cost, providing a new method for the construction of soft soil foundation projects in Indonesia in the future.

(Economic Reference News)

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