Highway Stabilization and Protection
Introductory Photo Essay VS_highway.pdf (vetiver.org)
Vetiver has made significant headway over the past 25 years in its application for highway stabilization where high-cost infrastructure needs effective protection against batter and fill erosion and slippage. Vetiver, with its high tensile strength (av 75 MPa) and resulting improved shear strength of soil, has proven effective for stabilizing highways particularly under high rainfall tropical conditions.
There are now many companies in Latin America, Africa and Asia that are offering their vetiver expertise and services for bio-engineering applications of VGT. The plant has long lasting positive impact on slope stabilization, and acts as a pioneer plant for native plants to establish on poor quality “c” horizon soils.
Sections of the 2000 km Ho Chi Minh Highway, Vietnam, were stabilized using Vetiver Grass Technology. Paul Truong prepared a photo essay showing the impact of vetiver grass over a fourteen year period. (2000 – 2014). We are indebted to Van Tran and Tran Man (former Vetiver Network coordinators in Vietnam for some of the photos and the incredible work that was performed on this highway that follows the alignment of Vietnam’s famous Ho Chi Minh Trail.
The work and impact of these VS applications have to be considered, with the test of time, successful.
There were some deep land slips (10 meter deep) that VS could not prevent, even so the overall results were excellent. Contrary to views of some critics the Vetiver System: (a) protected slopes of over 60%, (b) protected slopes against very high rainfall, (2000 mm per year) including extreme events under typhoon conditions, (c) provided a microclimate that allowed native plant species to naturally establish relatively quickly, eventually shadeing out the vetiver to the extent that in 2014 there is little evidence of vetiver in some of the earlier plantings – NOTE where native species did not establish vetiver continued to grow and protect the slopes, (d) resulted in a much reduced investment cost (estimated at 90% of hard engineering solutions), and minimum annual maintenance costs, and (e) proper engineering designs assured good results for VS application as a stand-alone technology or in combination with hard engineering technology.
The experience on this highway confirms that VS could be applied widely for slope stabilization in developing countries, where climate permits, and where labor is relatively cheap. It also confirms the need for good engineering design. Some that follow underscore these points
|On fragile slopes protecting high cost structures and subject to slippage engineered soil nailing backed by VS has proven a successful combination as shown in this presentation by Paul Truong|
|Vetiver System for Erosion and Sediment Control, and Stabilization of Steep Slopes||Power Point by Paul Truong (pdf MB 2.6) With special reference to Vietnam|
|Application of Vetiver Grass Technology in the Stabilization of Road Infrastructure in the Wet Tropical Region of Australia||Power Point by Paul Truong|
|The Vetiver System for Infrastructure Stabilization in Africa||This is a modified power point showing how VS has been used for slope stabilization in Madagascar. It also shows how local communities have benefited from the production of vetiver plant material. The author, Roley Noffke, is a highly skilled and experienced road engineer and has worked widely with various Vetiver System applications. He can be contacted by email.|
|Erosion control and vegetation restoration||Fixing a major sand dune in Madagascar. Carol Knoll and Roley Nöffke’s illustrated article in July/August 2008 issue of Environmental Management. South African company, Hydromulch (Pty) Ltd was involved in a major sand fixing, erosion control and slope stabilization undertaking for a newly constructed roads at the Rio Tinto/QMM Ilmenite Project at Fort Dauphin, Madagascar.|
MOUNTAIN ROAD PROTECTION COLOMBIA (including Vetiver)
|Meclas Ecologicas Parrael Control dela Erosion y La Estabilidad de Taludes English Spanish|