Largest GYRO PILER™ Deployed for Tsunami Protection Project in Iwate

GIKEN LTD. announced that its rotary cutting press-in machine for tubular piles GYRO PILER™ GRV2540 has been adopted for levee construction at the mouth of Hei River in Miyako-shi, Iwate Prefecture, an area struck by the Great East Japan Earthquake. Of the press-in machines developed by GIKEN, this GYRO PILER™ has the highest press-in capabilities and is capable of handling large-diameter tubular piles of up to 2.5 m. In this project, tubular piles with a diameter of 2 m were used to construct the levee’s foundation, creating a firm disaster-prevention infrastructure against future disasters.

This is a large-scale project to protect the streets of Miyako-shi from tsunamis by constructing a floodgate against tsunamis at the mouth of Hei River, integrated with the levees on both banks. With a total length of approximately 164 m, it is the largest such floodgate in Japan. GIKEN SEKO CO., LTD., a Group company of GIKEN, was in charge of installing the piles for the foundation of the levees. The initial plan was to install two rows of tubular piles with a diameter of 1,000 mm, but considering that using large-diameter piles can ensure high rigidity and also contribute toward shortening the construction period, tubular piles with a diameter of 2 m were adopted for this construction.

After the Great East Japan Earthquake, the Implant™ Method of GIKEN was adopted for a cumulative total of 231 cases in the Tohoku region’s six prefectures (Aomori, Iwate, Miyagi, Akita, Fukushima, and Yamagata) struck by the disaster. With a renewed commitment to our mission as a disaster-prevention company, the GIKEN Group will continue to devote our full efforts to improving regional disaster resistance and realising a safe and secure society while using the experience and knowledge nurtured through reconstruction projects.

During the Great East Japan Earthquake, there were tsunamis up to 11 m high (8.5 m at Miyako-shi). Water flowed up Hei River, flooding urban streets. Therefore, together with strengthening tide walls at coastal areas, Iwate Prefecture formulated a plan to install a floodwall 160 m in width at the mouth of the river and undertook construction in stages since 2014. The floodgate is equipped with four movable gates, with pillars up to 40 m high, making it one of the largest tsunami protection floodgates in Japan. Since 2017, the GIKEN Group has participated in two construction sections of the project, installing steel tubular pile foundations at regular spacing for the massive floodgate structure using techniques such as the Skip Lock Method™.

Construction of floodgate foundation undertaken over two sections since 2017

Construction was carried out concurrently with the extraction of tubular sheet piles used for the floodgate’s temporary cofferdam, but there was a constraint faced in securing space for the deployment of additional barges. Therefore, besides the main unit of the press-in machine, the GRB System™—which uses a large, 30-ton CLAMP CRANE™ capable of moving atop the piles—was adopted to achieve construction in compact space. As it was also required to install through existing concrete revetments and ground that had been improved during earlier floodgate works, the GYRO PILER™ was employed. This is a machine that can install tubular piles equipped with cutting bits using a rotary cutting function, allowing efficient installation without the need to remove obstacles beforehand and completing the installation of 27 tubular piles in a short period of time. Furthermore, small-diameter tubular piles with a diameter of 318.5 mm were installed between the main piles to prevent soil runoff into the river when filling in the revetment and to serve as part of the river levee structure upon completion.

After opening the Reconstruction Support Office in Sendai-shi, Miyagi Prefecture in July 2011, GIKEN has continued to propose the technology of the Implant™ Method centered on construction for restoration. Several earthquakes occurred in the 15 years since the Great East Japan Earthquake, but no significant damage was seen at sections where the Implant™ Method was adopted. This track record shows the high reliability and durability of the Implant™ Structure.

In the Tohoku region, beyond earthquake reconstruction, damage from typhoons and torrential rains also occur frequently, and GIKEN will further promote the use of the Implant™ Method for river improvement and dam construction going forward. The superiority of the Implant™ Method—in fields such as the development of ports with a view of navigation by large ships and the development of infrastructure related to offshore wind power generation—will also be widely communicated.

■Profile of GIKEN Group
GIKEN developed the SILENT PILER™, the world’s first reaction-based, non-vibratory hydraulic pile driving machine that operates with minimal noise impacts. The GIKEN Group now actively promotes its press-in technology worldwide and contributes to the construction industry by proposing and implementing innovative solutions. The innovative press-in technology provides a unique solution and the adoption of this technology has spread to over 40 nations and regions.

If you have any questions regarding the news release, please feel free to use the provided form to inquire.
Contact Us