Prevention measures are necessary when unstable slopes threat infrastructures, thus hampering local economies and interrupting local communities’ logistics
A geological phenomenon that can suddenly occur, without the slightest warning, debris flow is one of the most dangerous water-laden mass events.
Its name, “debris flow” is quite literal – debris; that can include anything from micro-sized mud particles to devastatingly large boulders. Descending down valley slopes, rapid flow of debris sweeps trees, concretes, cars or anything dare standing in its path. Many types of measures are taken to mitigate, divert or catch the debris. Because of the abrupt occurrence and the enormity of its wreckage, these measures are carefully studied and monitored for maximum protection.
The bigger the items washed, the bigger the problem is. Along the Simpang Pulai-Lojing Highway in Gua Musang, Kelantan, mud sludge left a wrecking path on a hill slope at Section 62-4 to 62-8. An estimated 4,000 m3 of debris flow washed down the 20° – 35° slope gradient. Due to loosened trees and fragmented rocks, the same location is in danger of recurring debris flow at a more devastating level.
Hence, the Public Works Department of Gua Musang, Kelantan, sought a solution to this problem. After a few visits to the site to study the condition, Maccaferri team found that our flexible debris flow barrier was the best solution to mitigate this condition. Three debris flow barriers with energy capacity of 3,000 kJ were constructed along the flow path. As an additional barrier, a gabion embankment was installed at the final point.
The barriers consisted of high strength yet flexible steel cable nettings, connected to a series of specially designed energy dissipaters aimed at absorbing kinetic forces during big impacts. The flexible barriers allow mud sludge and other smaller particles to pass through, while simultaneously catching harmful bigger objects in the nettings. It also acts as check dams to reduce velocity during an onslaught of rapid mud flow. The final volume of mud slurry that pass through the barriers will be obstructed by the gabion embankment at the slope toe.
By that time, the speed and impact of the assault would have been reduced tremendously. The 3 barriers stretched 30-meter-long across the flow path and stood on 5.5-meter-high posts.
For further technical information, please download the Case History.
For more info about our debris flow solutions, please contact us!