Volume 3, Issue 1 March 2018

On-site Interview

Gyropress (Rotary Cutting Press-in) Method in Disaster
Recovery Project (Kagoshima Prefecture, Japan)
Ms. Hongjuan HeIPA Secretariat

I interviewed Mr. Tsukasa Hashida and Mr. Issao Umiji
who belong to GIKEN SEKO CO., LTD. and were working
on the project “Disaster restoration on the No. 759
Road, Kagoshima Prefecture”. The steel tubular piles
were installed by the Gyropress Method as an earth
retaining wall. I thank them for giving us valuable
insights during this interview.
Photo 1 Construction overview
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Profile of Mr. Tsukasa Hashida, Project Manager of GIKEN SEKO CO., LTD.
Mr. Hashida entered the GIKEN Group in 1979. Until now, he has been operating variousmodels of Silent Piler including the KGK-100D which was firstly sold in 1978. He has
worked on many sites for 38 years and has been engaged in the Press-in Method suchas the Hard Ground Press-in Method, the Gyropress Method and others. He was theprime operator in this project. He has qualifications of “First-class Civil Engineering
works Execution Managing Engineer”, “First-class Press-in Operation Engineer”, thelicenses for various cranes and etc.

Profile of Mr. Issao Umiji, Project Manager of GIKEN SEKO CO., LTD.
Mr. Umiji has been working for GIKEN Group since 1980 with 11 year experiences in thePress-in Method such as the Gyropress Method, the Hard Ground Press-in Method andothers. He had experiences of working on abroad such as Asia and Europe. He wasresponsible for operating in this project. He has the qualifications of “First-class Civil
Engineering works Execution Managing Engineer”, “First-class Press-in Operation
Engineer”, the licenses of various welding and etc.

Q1. Please tell us about the background and summary of the project.
Mr. Hashida: In June 2016, a heavy rainstorm occurred in Kyushu region in Japan, which caused serious flooding andoverflowed their banks and flooded neighboring areas. Furthermore, there occurred serious flow disasters.
This construction site is at the Udo Bridge located on the Kagoshima prefecture road 72. The massive
landslide around the abutment occurred due to the heavy rain, eventually (Photo 1). This is a disasterrecovery project conducted by the Gyropress Method, preventing the bridge abutment from collapsing.

Q2. Can you tell us why the Gyropress Method was adopted and what the features of this construction?
Mr. Umiji: The key feature of the project was to use the “Non-staging
Method”, which could work on a slope near the bottom of
the bared abutment (Photo 2). If the conventional
construction method had been adopted, it should have built
an embankment and a temporary platform as a working
space on the eroded slope firstly. Then the installation of thesteel tubular piles were carried out. Actually, the Non-staging
method does not require temporary works, meaning that
additional works are not necessary. Due to the advantages of
the Non-staging Method (i.e. short construction period, lowcost and safety), our proposal was adopted.
Photo 2 Non-staging Method

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Q3. Was the project completed in accordance with the plan? If there were any difficulties, can you tell
us about it and how did you solve it?
Mr. Hashida: The press-in operation for which we wereresponsible was successfully completed (Photo 3). I think themost difficult thing in this operation was to decide theinstallation line. The longest steel tubular pile was as long as
24.5m, which the projecting length was 9m from the groundsurface to the pile top (Photo 4). There was nothing around thesteel tubular pile above the ground, it was very difficult when
we decided the installation line. This was also the curve piling,
and the angle of the installation line between adjacent steel
tubular piles was different. In a narrow area with a radius of 10meters, the operation was really tough. We used the pile laser
to determine the location of the piles with the main contractor.
It took 4 hours to fix the location of a steel tubular pile.
Photo 3 A view of after Press-in operation9m

Photo 5 Water lubrication System

Photo 4 Construction yard

Mr. Umiji: I also think it was difficult to decide the installation line. One of the reasons for the difficulty was that we did
not have the soil data, so we could not assume underground conditions before the installation. At thebeginning of the piling work, the steel tubular pile hit hard rock in a shallower place where we did not
anticipate the existence of it. We used the water lubrication system which can reduce pile toe resistance andthe plugging inside the steel tubular pile (Photo 5). But when we used the water lubrication system, thesludge, which soil and water were mixed, was discharged to the foot of the mountain. Because there werefarmland at the foot of the mountain, so the main contactor had to conduct the turbid water treatment. The
turbid water treatment was not directly involved in the procedure of the press-in operation for which wewere responsible, however, the duration of the project was extended.

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Volume 3, Issue 1 March 2018

Q4. Please share with us your impressive experience.
Mr. Hashida: The most impressive experience was that I drove the Silent Piler firstly when I
just entered the company. Our company firstly sold the KGK-100D model ofSilent Piler in 1977 (Photo 6). My first press-in operation was to drive this Silent
Piler. At that time, the maximum SPT N value in the soil boring log was only
about 10, which I considered that the operation should be easy. But when theSilent Piler pressed-in the steel sheet pile to about 10m deep, the machine tilted
forward and it was difficult to continue the operation. At that time, I didn't know
how to recover the situation because there were not any construction manuals.
This experience was very remarkable to me. Now, a variety of machines havebeen manufactured, and the automatic driving system has become real. I reallyamazed the rapid progress of Press-in Technology.
Photo 6 KGK-100D
type of Silent Piler
Mr. Umiji: For me, the experience of the first overseas construction in 1983 was the most impressive. In fact, thisconstruction was also the first achievement of the Press-in Technology used overseas. The place of theconstruction was in Giessen city, Germany. The project was to build a new city government office, and thePress-in technology was utilized to construct the retaining wall of the office building. Because I was only one
Japanese on the site in Germany, I had a strong anxiety about language and culture. And the ground conditionof the site was very stiff, overall, the piling progress was not very smooth. Through the interpreter to help
me to train the local staffs, we completed the project with our local staffs together.

Q5. Were there any differences when you operated in Germany?
Mr. Umiji:

Yes. I think there is a great difference between the working culture of Germany and Japan. In Germany, thebreak time was clearly defined. Even when the installation into the ground was undergoing, if it comes tothe break time, they had a break immediately. If this happens in Japan, Japanese labors should have a breakafter the completion of the installation. Because I didn’t know the culture, the progress of the project was
not the way I expected. I think it's important to understand different local culture and rules in overseas
constructions.

Q6. What is your prediction about the future of the Press-in Technology?
Mr. Hashida: I guess that fully automated operation will be true in 10 or 20 years. When I just entered the GIKEN Group,
I had no operation manuals and learned the Press-in Technology through ten years of work. I think that thehandbook will be improved, the technology of AI and mechanism will be evolved, and everyone will be able
to be a good operator shortly in the future. I do not want young generation to spend 10 years, learning thePress-in technology like me. As you know, Japan's population is decreasing sharply. If the operation could
be fully automatically conducted, it may solve the issue of insufficient labor population. And it could be safer
to conduct even in dangerous places.
Mr. Umiji:

In the future, I hope geological visualization can be achieved by using Press-in technology. Now, we do notknow how the toe of the piling works, nor can we assume the underground obstructions. If you can watch
the condition of the underground, the machine's autopilot technology should also improve faster. I don't
know if it's going to come true, but for example, installing a small camera at the toe of the pile so that wecan watching video while installing the piles.

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★ Comments
This time I did not visit the site of the construction, but
through the communication with the Mr. Hashida and Mr.
Umiji, let me understood the whole situation of theproject. Mr. Hashida has been in construction for 37 years,
and he has been driving from the KGK-100D model of Silent
Piler to the latest series of Pilers. It seemed to me that hegrew up together with Silent Pilers to witness the historyof Silent Piler’s development. Mr. Umiji broke through thebarriers of language and culture to complete the project inGermany by himself. I really admire his unremittingperseverance. I also felt strongly that in this construction,
Mr. Hashida and Mr. Umiji made great efforts to achieve
the project. I really thank them for giving us valuable
insights during this interview.
Photo 7 The view of interview

Photo 9 Mr. Umiji is driving the Piler

Photo 8 Mr. Hashida is driving the Piler

I would like to express my sincere appreciation toward Mr. Hashida, Mr. Umiji and all who are concernedin this interview. Thank you so much.
We welcome the on-site operators who are able to accept the interview. If you have any questions, pleasecontact to IPA Secretariat address to Ms. Hongjuan He (ipa.ka@press-in.org). We are waiting for you!

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