JSCE Site Excursion & Joint Company Information of Kita-Osaka Kyuko Line Extension Project

Written by Karina Sujatmiko, Okumura Lab D1

On 25 November 2019, the Japan Society of Civil Engineer arrange a visitation to the ongoing construction of subway. The participant are professor and international student from Kyoto University and Kansai University. This construction project named as Kita-Osaka Kyuko line extension project. The new subway will be connected from Senri-chou to Minoh with the length about 2.5 km. This subway will have two station, Minoh-semba handai mae and Minoh-kayano. 

There was four main activity in this event, project presentation, field survey, company profile presentation and company interview. All this activity given by four companies that responsible for this construction. Those four companies are Obayashi, Taisei, Kumagai and Pacific consultant.

The first location we visited was the elevated section. Due to the crowded traffic, many housing and high elevation there are many variations and technique of the pile construction. 

Some pillar can be build using the standard size and material (cast in place concrete pile) while the others need bigger size and stronger materials. The design and construction of the standard pillar design has eight piles made by concrete. However, in the narrow area the pile has to be bigger and use stronger materials, like steel pile or ring caisson foundation. Standard piles staking between 15 – 40 m depth but the stronger pile stacking up to 52 m depth. 

Figure 1. Visiting the construction of P12 pile in the elevated section area.

The second location was the open cut tunnel section. This area consists of the minoh-semba handai mae station (around 225 m long), line tunnel (around 440 m) which connect to the viaduct (total length 625m). The segment between the two viaduct is carefully plan and construct because it is crossing Senri river. The station construction makes me wonder because it has three level and support by a lot of steel pile. I eager to see what it will look like after the station finished.

Figure 2. Walked down towards the construction of Minoh-semba underground station.

The last location was the shield tunnel section. When I was in Indonesia, I read the news about the Jakarta MRT that was construct by the Japanese company.  Before I only saw the machine and tunnel from the newspaper picture, so I was glad to have an opportunity to directly saw. Surprisingly, to operate this machine only need one person because everything controlled using a computer. Considering they were digging I suspect there will be mud and dirt everywhere, but it was amazingly clean and well organized. 

Figure 3. Kumagai gumi company representatives explained about the mud dumping from the underground shield tunnel.

In company profile and interview session, I learn about the Japanese company ethic and their vision. I like their strategies to always find new technique and technologies by creating research and development facilities. 

Figure 4. A warm welcome sign in Obayashi construction area, the open cut tunnel section.

In this event, I not only learn about civil construction and companies, but also, I made new friends. They are coming from Myanmar, Nepal, India, Kenya, Iran and many others. It was very fun to discuss and sharing knowledge with them.