Validity of the “Technology for Tenacious River Levee Protection” public contest was confirmed.

(Tokyo Head Office: Setagaya-ku, Tokyo; Osaka Head Office: Yodogawa-ku, Osaka; President: Yumi Nomura), a manufacturer of large membrane surface structures (tent structures), civil engineering and logistics materials, has applied for the “Technology for Tenacious River Levees against Overtopping,” an open call for entries issued by the National Land Engineering Research Institute in March 2023, The application was made by the National Institute of Land and Infrastructure Management (NILIM) for our product, Breathable Sheet, an air-permeable waterproof sheet. The effectiveness of the Breathable Sheet in overtopping was recently confirmed through a full-scale overtopping test with a levee height of 2.5 m, a top edge width of 3.0 m, and a slope of 1:2.0. In order to respond to the increasing frequency and severity of flood damage caused by climate change in recent years, further confirmation of performance and accumulation of technical reliability will be promoted through pilot construction on actual levees in the future.

It is a three-layer integrated sheet consisting of an air-permeable waterproof sheet with excellent waterproofing and air permeability sandwiched between protective mats, which prevents rainwater and river water from infiltrating into the embankment and allows air permeation over the entire surface of the sheet. When the infiltration surface inside the embankment rises due to rising water, the pore air is quickly discharged, preventing the poreairpressureinsidethe embankment from rising, air blow phenomenon, and damage to the embankment. The system has already been used in the reinforcement of the Yahagigawa River embankment in Aichi Prefecture (March 2021).

https://www.taiyokogyo.co.jp/products/10097/

The National Land Technology Research Center, a third-party organization selected by the Ministry of Land, Infrastructure, Transport and Tourism in September 2022, has issued a public call for applications. The public call period is from March 10, 2023 to September 11, 2023.

https://www.jice.or.jp/nebarizuyoi

Eighty-six percent of the major causes of levee breaches caused by Typhoon No. 19 in 2019 were due to overtopping. Therefore, even if water overtopped the levees, there is a need to develop “tenacious river levees” that allow residents time to evacuate and extend the time until the levees collapse, even if only a little. As a guideline for technological development to evaluate the performance of levees against water overtopping, the following was set as a guideline: “The structure shall maintain its performance against water overtopping for 3 hours against an external force of 30 cm in overtopping depth, based on the knowledge of damage conditions, overtopping depth, overtopping time, and time required for evacuation in recent cases of overtopping. The structure shall maintain its performance against water overtopping for a period of 3 hours against an external force of 30cm depth.

The water level was kept constant after rising at a constant rate to a depth of 30 cm, and an overflow test was conducted for more than 3 hours. The deformation (erosion prevention effect) of the embankment top-edge protection, shoulder protection, back slope protection, back slope butt protection, and drain were confirmed by visual observation and level surveying. To confirm the reproducibility (reliability), we conducted the experiment three times under the same conditions.

The difference in the average measured height of the embankment before and 3 hours after overtopping was less than 8 mm, and the height of the embankment was maintained in all three overtopping tests. Visual observation showed that no deformation was observed at any of the locations, and the levees remained coated with the surface coating material. No damage such as seepage or erosion was observed on the embankment surface, confirming its erosion-resistant performance.

The evaluation hierarchy for the submitted technology was determined to be “Category B,” and the breathable waterproof sheet “Breathable Sheet” was evaluated as desirable for continued technological development.

Taiyo Kogyo is a leading manufacturer of large membrane surface structures that are economical, easy to install, translucent, and well designed. Under the corporate philosophy of “Unlocking the infinite possibilities of membranes to deliver an inspiring and comfortable environment to our customers. Under the corporate philosophy of “We will bring excitement and a comfortable environment to our customers by exploiting the infinite possibilities of membranes,” TSP Taiyo has been supporting the safety and security of society by utilizing the characteristics of light and strong materials to expand its business in various fields including construction, as symbolized by the roof of the giant dome, civil engineering, logistics, and environmental fields.

Together with group companies such as TSP Taiyo Corporation, which provides event consulting services, and ACTIO Corporation, which manages facilities, we are working to “make the world softer and the future warmer. We aim to “make the world soft and the future warm. TSP Taiyo Corporation, the event consulting firm, and Actio Corporation, the facility management firm.

Photos for the press can be downloaded from here.