Preventing Slope Collapse│What are effective concrete measures for slope protection?

Due to the characteristics of its land, Japan tends to suffer from many natural disasters such as windstorms and earthquakes. Each time this happens, news has been reported of slope collapses that have occurred in various areas. In such cases, immediate action is needed to prevent secondary disasters.

In order to prevent landslides and collapses, it is extremely important to carry out slope protection work on a regular basis. In this issue, we will look at examples of slope collapses and their mechanisms, and introduce countermeasures and slope protection construction schemes.

For concrete canvas product page,please visit

For inquiries about our products, please contact ushere.

Slope Collapse

Slopes are so unstable that they are always in the process of collapse and are vulnerable to natural disasters. When slopes associated with transportation infrastructure, especially highways and railroads, collapse, the impact on the transportation infrastructure can be devastating, and the economic loss can be enormous.

For example, a slope adjacent to a highway collapsed 7 meters high and 150 meters wide, and it took nearly six months for full traffic to resume. The slope, which had been protected by vegetation, became vulnerable due to rainwater infiltration, and eventually collapsed.

In another case, a 15-meter-high, 20-meter-wide slope built with fill beside a railroad track collapsed. It took a long time to resume operation after emergency measures were taken. The slope was not reinforced with concrete or other protective measures.

See also:Download Slope Protection Document

Mechanism of slope failure due to rainfall

法面には切土法面・盛土法面の二種類があります。これは法面を作る時の方法によって分類されるもので、前者は斜面を切り取ることで作った法面で、後者は逆に斜面に土を盛り付けることで形成された法面です。

これらは降雨によって深刻な劣化がもたらされ、法面の崩壊が発生、場所により甚大な被害へと繋がります。

それでは降雨により法面はどのような経緯で崩壊に至るのでしょうか。切土法面では、特に切りっ放しの法面や植生が根付いていない法面の表面に雨水が流れることで、表層が浸食を受けたり崩落したりする場合があります。切土法面が真砂土や砂、火山灰土など土砂で構成される場合に発生しやすく、放置すると表層からより深い崩壊にもつながります。

盛土法面の場合でも、植生が十分でない状態などで降雨に曝されると、表面が浸食され、崩壊に繋がります。また、表面水が集中しやすい箇所や、跳水の発生しやすい水路周辺などでは、降雨による浸食や洗堀が発生しやすく、豪雨により排水溝がオーバーフローし周辺の法面が浸食される場合もあります。これらの浸食は、雨水流出量が多大となればより深く広い範囲に影響があり、崩壊も大規模なものへ繋がってしまいます。

台風の大型化や線状降水帯の発生により豪雨の規模と頻度が増加している近年、法面への雨水流出量も増え、「常に崩壊するかもしれない」という想定を行っておかねばならないと言えます。その為にも普段からの法面保護工事の実施が必要となるのです。

What is a concrete canvas with strengths in workability, durability, and flexibility?

Concrete Canvas” is a composite material of concrete and canvas (fabric) that hardens when moisture is added. It combines the properties of both fabric and concrete, and features ease of installation, durability, and flexibility.

workability

One concrete canvas weighs about 70 kg. Since it can be freely cut on site, it can be transported and installed by hand even in areas where heavy machinery cannot enter. This reduces the time and cost of installing plants and securing heavy equipment.

durability

As with concrete, the extent to which it can withstand degradation from ultraviolet rays is crucial outdoors. Concrete canvas has been tested by British Standard weathering tests to be able to withstand outdoor environments for at least 50 years.

flexibility

Until it begins to harden, it has the properties of a fabric and can flexibly conform to even complex shapes of ground. It can also be cut with a cutter knife, allowing for fine adjustments to suit the site, and is used not only for slopes, but also for reinforcing drainage channels and various other applications.

Related information: Download Slope Protection Resources

summary

Slope protection work to prevent slope collapse, which causes many economic losses, is costly and time-consuming.

Concrete canvas, however, is easy to use, low cost, and its durability reduces post-construction maintenance costs. Please visit our official website to learn more about the many examples of our products already in use by local governments and other varied organizations.