Jakarta, October 10 (Reporter Li Zhiquan, intern Chen Shimeng) Indonesian President Joko Widodo announced the official opening of the Yawan high-speed railway at the Halim high-speed railway station in Jakarta, the capital of Indonesia, on the morning of the 2nd. The project starts from Jakarta, the capital of Indonesia, and ends in the tourist city of Bandung, with a total length of 2.142 kilometers. Little known to the outside world, there are 3 tunnels and 13 bridges along the Yawan high-speed railway, including the largest railway shield tunnel in Southeast Asia and the first longest bridge of the Yawan high-speed railway.

On October 10, Indonesian President Joko Widodo announced the official opening of the Yawan high-speed railway at the Halim high-speed railway station in Jakarta, the capital of Indonesia. Heads of the Chinese Embassy in Indonesia, China Railway International Co., Ltd., Indonesia China High-Speed Railway Co., Ltd. and other units attended the opening ceremony. The picture shows the EMU train stopping at the ceremony. Photo by Li Zhiquan

The "Four Most" of the Yawan High-Speed Rail Tunnel

The Yawan high-speed railway has a total of 13 tunnels with a total length of 16.69 km, all of which are single-hole and double-line tunnels. There are mainly "four most":

Tunnel 1, the largest railway shield tunnel in Southeast Asia. Located in the capital Jakarta, about 2.5 kilometers away from Halim Station, the starting station of the high-speed railway, with a total length of 1885 meters and a maximum buried depth of 34 meters, it is a control project for the whole line. The tunnel passes through the light rail, highways and built-up areas under construction, and passes through two mosques on the side, with abundant groundwater and surface water, complex construction conditions, and difficult projects. During the tunnel construction process, the "shield + cut-and-cover" construction method was accurately adopted, and the ultra-large diameter shield machine independently developed by China was used, and the excavation diameter reached 13.23 meters, the largest in Southeast Asia. On December 2020, 12, the No. 15 Tunnel of the Yawan High-Speed Railway was successfully completed, and the Indonesian Ministry of Public Works and Housing awarded the largest TBM (tunnel boring machine) award certificate for the No. 1 tunnel project in Indonesia.

The longest tunnel on the entire line, Tunnel No. 6. Located in Puvacada County, northwest of Bandung City, with a total length of 4478,2022 meters, it is the longest tunnel in the whole line. The tunnel is located in a low hilly area, the geology is clay, mudstone, volcanic breccia accumulated by early volcanic eruptions, the groundwater table in the tunnel is high, and the tunnel is long distance through shallow buried layers, which is difficult to construct. The construction unit adopts various construction methods such as advanced geological forecasting, additional lock feet, and side wall grouting to ensure the construction progress and construction safety. On February 2, 18, Tunnel 6 was successfully completed.

The tunnel with the highest construction risk in the whole line - Tunnel 10. Located on the outskirts of Bandung city, it is 1230 meters long. The surface of the tunnel is mainly distributed as rice fields, and the outlet is for villages and towns, with a maximum buried depth of 37 meters. The tunnel passes through the existing operating railway with a curve radius of only 200 meters under the entrance section, the buried depth of the lower section is shallow, the surrounding rock is poor, the tunnel cave is weak surrounding rock, and the water volume is abundant, and the construction is easy to cause subgrade settlement, which poses risks to the safety of existing railway operation. The construction unit adopts precision monitoring and measurement, longitudinal and transverse beam reinforcement, surface grouting and water stopping and other technical processes to ensure the construction progress and safety. On August 2021, 8, the No. 6 tunnel of the Yawan high-speed railway was successfully completed.

The most difficult tunnel to construct on the whole line - Tunnel 2. Located in Puvakarta County, West Java Province, it has a total length of 1052 meters and a maximum buried depth of 53.6 meters. The geology of No. 2 tunnel has the characteristics of "four high and one strong" with high water content, high liquid limit, high compression ratio and high porosity, and encounters problems such as collapse, settlement deformation, and mud intrusion, which is the most difficult tunnel for the construction of the entire Yawan high-speed railway. The construction unit dispatched 68 tunnel and grouting professional backbones from various projects at home and abroad, and innovatively adopted the excavation method according to local conditions to realize the virtuous cycle of "fast excavation, fast support and fast ring" of soft surrounding rock tunnels, effectively controlled the settlement deformation, and ensured the safe and smooth progress of tunnel construction. On June 2022, 6, the No. 21 tunnel of the Yawan high-speed railway was successfully completed, which is also the last tunnel of the Yawan high-speed railway to break through.

On the morning of October 10, local time, Indonesian President Joko Widodo announced the official opening of the Yawan high-speed railway at the Halim high-speed railway station in the capital Jakarta. The picture shows the conductor reporting to Jokowi before boarding. Photo by China News Agency reporter Li Zhiquan

"Innovation" of Yawan high-speed rail bridges

The Yawan high-speed railway has a total of 56 bridges with a total length of 88 kilometers. During the construction process, the design department implemented the innovative design of simple support box girder for the Yawan high-speed railway.

Innovative design of simple support box girder to improve the seismic efficiency of bridges. Java Island, where the Yawan high-speed railway is located, is located at the intersection of the three major plates of the Eurasian plate, the Pacific plate and the Indian Ocean plate, with an earthquake intensity of 8 to 9 degrees, and frequent volcanoes and earthquakes. In order to reduce the impact of the earthquake on the bridge, the design department implemented the innovative design of the simple support box girder for the Yawan high-speed railway, reducing the self-weight of the simple support box girder body, reducing the weight of about 100 tons compared with the domestic general beam, with a weight reduction of about 12%, and carried out full safety verification.

The first long bridge of the Yawan high-speed railway - No. 2 special bridge. With a total length of 36 kilometers and a total of 24 continuous beams, it is close to the Jakarta Bandung Expressway, with a narrow construction site and a complex surrounding environment. The construction unit scientifically formulated a sectional erection plan, which minimized the impact of the adjacent highway on the construction and ensured the smooth closing of the continuous beam group. On June 2022, 6, the erection of the last hole box girder was completed, opening up the track laying channel of the entire line.

The bridge that crosses the largest river on the Yawan high-speed railway line, the No. 17 Special Bridge. It is 2.8 kilometers long and is located in Pougada County, Java Province, spanning the Chitarong River, which has the largest flow and widest riverbed in the entire line. Since the start of construction, the construction unit has in-depth study of the surrounding area of the bridge site and the local hydrogeological conditions, made full use of the construction during the dry period, erected the longest trestle bridge in the whole line, and innovatively used construction measures and technological methods such as the foundation locking pipe pile cofferdam. On December 2021, 12, the erection of the last hole box girder was completed.

It is understood that in the process of the construction of the Yawan high-speed railway, all participating units have comprehensively strengthened the control of the ecological environment and built an ecological environmental protection road. First, in accordance with the relevant laws and regulations of Indonesia's environmental management system, do a good job in soil and water conservation and environmental protection of the waste site. The second is to minimize construction noise, so as not to disturb the people and civilized construction. The third is to keep the construction site clean. Fourth, after the completion of the project, the site will be sorted out and the original terrain will be restored. The roadbed construction is synchronized with the greening of the slope to create a green corridor. (End)