Volume 2, Issue 2 June 2017

Interview

On-Site Interview
Ms. Hongjuan HeIPA Secretariat
I interviewed Mr. Matsuzawa (Sato Jyuki Kensetsu Co., Ltd.) and Mr. Asano (Kajikawa Construction Co., LTD) who are
engaged in the Press-in project named “Aseismic reinforcement work to embankment on Turumi – Shinkoyasu line”, On
March 3rd 2017, at Yokohama city, Kanagawa prefecture. I thank them for giving us valuable insights during this interview.
Satojuki construction Co., Ltd is responsible to manage the entire project and conduct the Press-in operation on inboundline (for Tokyo). Kajikawa Construction Co., Ltd conduct the Press-in operation on outbound line.
Profile of Mr. Kazuyuki Matsuzawa, Sato Jyuki Kensetsu Co., Ltd.
Mr. Matsuzawa has experienced in construction industry for 28 years. He has joined Sato JyukiKensetsu Co., Ltd. in 2013 with his career of construction management in piling. He is responsible forconstruction planning, management and quality control in welding work as the construction manager
in this project. He has qualifications of the First-class Civil Engineering Works Execution Managing
Engineer, the Second-class Welding Engineer, the licenses for various cranes and construction
vehicles and etc.

Profile of Mr. Yoshikazu Asano, Kajikawa Construction Co., LtdMr. Asano has joined Kajikawa Construction Co., Ltd. in 2009 with 8 years of the field experiences on
the “Hard Ground Press-in method” and other application of the Press-in method. He was engaged
as a main operator for this project. He has qualifications of the Second-class Press-in Operation,
Supervisor for safety program in charge and so on.

Q1. Can you explain the background, overview and features of this project?
Mr. Matsuzawa: As everyone knows that the Great East Japan Earthquake happened in 2011 and brought a severe damage
to Japan. Therefore, Japanese government has committed the aseismic reinforcement projects of therailway embankment to minimize damages due to an inland earthquake in Tokyo area. The project isordered to press-in 120 pieces of U shaped steel sheet piles (L=16.5m) to the both side of inbound andoutbound lines then the top of parallel steel sheet piles are connected with tie rods.
Mr. Asano:

The significant characteristic of the project is to conduct press-in operation on the very steep and narrowslope adjacent to the railroad during day time. As shown in the Picture1, the workable construction spaceis limited in 4.5m to 10m width for inbound line and 2.5m to 3.5m width for outbound line for 60m lengthon each line. Vibration was strictly limited during the operation since the distance from the safety guard
fence along the railway was only 1.6m away as shown in Picture2. It was required to pay very carefulattention particularly for material hoisting process since trains are passing by every 5 minutes in morningand evening commute.

12Volume 2, Issue 2 June 2017

60m

60mPicture1: Construction overview
Red frame: Construction for inbound line
Yellow frame: Construction for outbound line

1.6ｍ

Picture2: Non-staging system (outbound line)

Picture3: Side-view

Q2. What are the significant points for the Press-in Method to overcome constraint conditions on theproject?
Mr. Matuszawa: It is impossible to utilize the conventional methods which require to place the necessary machines andequipment side by side on the narrow and steep slope. We introduced the Non-staging system, as shownin Picture 2, that the system only enables all the piling machineries for the Press-in operation to walkon the previously installed sheet piles by itself (self-walking).

13

Volume 2, Issue 2 June 2017
Q3. Has the construction been carried out on time? Can you tell us about difficulties or concerns that you
have faced on the project?
Mr. Asano:Yes, the construction has been carried out smoothly so far and we predict that theproject will be completed earlier than planned schedule. The Press-in operation
has completed on the outbound line yesterday and the self-walking backward
operation has just commenced today, and it is projected to complete in two days.
We have judged that the ground condition will be relatively easy to deal withbased on the given soil boring log, but we found obstacles in 14m depth as shownin Picture 4, unfortunately. We have continued the operation since the Crush Piler
enables to penetrate those obstacles. I reaffirmed that the Press-in method isversatile and applicable to deal with varieties of ground conditions, applicable tohard ground again through this project.

Picture4 obstacle

Mr. Matuszawa: The progresses was made generally on time but have experienced difficulty to carry-in the machines andsheet piles to the construction space. We introduced 200 tons all terrain crane to carry the equipment
and materials over the railways because the large vehicle is unable to access to the construction yard,
then we divided the Crush Piler into two segments to hoist them in with the crane. Electric supply is cutoff only for 2.5 hours between 1:00am to 3:30am and we are required to safely carry in the equipment
and materials during the limited time period. We carefully made the plan that all necessary equipment
and materials are kept in the temporary stock yard just outside of the railways then hoist them over tothe construction yard during 2.5 hours. However, we could not execute it in the winter season
occasionally because trains need to be run in the mid night to prevent the rails to freeze. We havelearned that the construction plan need to be carefully examined to absorb those unpredictable
incidents.

Picture5 carry-in the equipment

14

Volume 2, Issue 2 June 2017
Q4. Were there any specific requirements from project clients?
Mr. Matsuzawa: Safety is the most important issue than anything else. The first priority is to assure the safe train operation.
If accidents do happen due to rush of construction, it will cause enormous effects on the train operationand passengers, though it is important for us to complete our construction soonest possible. Since weare dealing with sheet piles, we extremely care to prevent scattering of metallic noise with anti-noise
sheets around the construction area.

Q5. Please share with us your toughest operational experience.
Mr. Asano:I experienced difficulties to dear with underground obstacles where I conducted the Press-in work withthe Zero-clearance Crush Piler in Gifu prefecture two years ago. I was aware that the gravel layer wasexisting 6m below the ground surface according to the soil boring log, which the Crush Piler should nothave any problems for penetration. I observed the Press-in operation became difficult though and I felt
very rushed due to lack of my experience, then I asked for my seniors’ advice for problem solving. With
having their advice, I have learned that even though the soil boring log is important but the predictionof problems by hearing the sound during augering process and making an appropriate judgement is very
important on the job site. The advice is still useful in this construction.

Mr. Matsuzawa: I also experienced difficulties at project of aseismic reinforcement to embankment at Takadanobaba,
Tokyo three years ago. The project was ordered as the steel sheet piles Press-in with Crush Piler inaccordance with the specifications but some H shaped steel piles were left in the ground. We tried toextract H shaped steel piles (12 m in length!) with Crush Piler and its successfully done, otherwise wemight have to divert the press-in line from the initial plan. The extra efforts ended up with adjustments
to construction schedule with re-arrangement of manpower and machines. Through this experience, I
become keenly aware of the importance of the on-site inspection to identify the existing condition
before the commencement of the work.

Q6. Please share your prediction with us about the future of the Press-in Technology.
Mr. Matsuzawa: GRB system (Non-staging System) is the system that enables all the piling machineries necessary for thePress-in operation to move by itself (self-walking) on the previously installed sheet piles. It hasenormous advantage compared to other methods which require other construction machineries tooccupy large area besides piling machine. Especially, Japan has a large amount of earthquake. We
believe GRB system (Non-staging System) is effective method for expeditious restoration works at
disaster area cause by earthquake and/or tsunami.
Mr. Asano:

I fully agree with what Mr. Matsuzawa said. I often use GRB system on construction site. I hope we could
use GRB system without using heavy machineries such as rough terrain crane. Also, I will make more
effort to become much better by utilizing the Press-in System so I could contribute myself more througha lot of construction sites.

★Comments:
For this interview, I went to the site where Press-in machine was in operation and was so surprised that I knew that thePress-in Method could use under the restricted circumstances such as narrow space and limited construction time innight. It was very impressed that the trains I watched at construction site were felt much larger than what I see them indaily life. When those train are passing by, the site staff ceased their work, giving the train driver hand signal to assure
safety with facing to huge train. I was so impressive by their attitude towards safety issue. Moreover, I found it amazinglythat no claim has been received from the neighbors because of trust relationship between them and the site staff being
well developed, though the construction site is surrounded by family houses. Through this interview, I strongly felt thatthey are proud of not only the Press-in Method but themselves, which they have experienced a lot through having hardtime to deal with difficult situations.
I believe that the Press-in application adjacent to railway will be a very useful case-example internationally so that I would
like to continue to introduce similar topics in our Newsletter.

15

Volume 2, Issue 2 June 2017
I would like to express my sincere appreciation toward Mr. Matsuzawa, Mr. Asano and all who areconcerned in this interview. Thank you so much.

Picture 6: Interviewing with Mr. Matsuzawa and Mr. Asano

Picture7 Mr. Matsuzawa is checking
lateral joints on the site

Picture8 Mr. Asano is operating the system ofself-waling backward

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!

16