Use of Vegetation and Geo-Jute in Erosion Control of Slopes in a Sub-Tropical Climate

Authors: Mohammad Shariful Islam, Shamima Nasrin, Md. Shahidul Islam, Farzana Rahman Moury

Abstract:

Protection of slope and embankment from erosion has become an important issue in Bangladesh. The constructions of strong structures require large capital, integrated designing, high maintenance cost. Strong structure methods have negative impact on the environment and sometimes not function for the design period. Plantation of vetiver system along the slopes is an alternative solution. Vetiver not only serves the purpose of slope protection but also adds green environment reducing pollution. Vetiver is available in almost all the districts of Bangladesh. This paper presents the application of vetiver system with geo-jute, for slope protection and erosion control of embankments and slopes. In-situ shear tests have been conducted on vetiver rooted soil system to find the shear strength. The shear strength and effective soil cohesion of vetiver rooted soil matrix are respectively 2.0 times and 2.1 times higher than that of the bared soil. Similar trends have been found in direct shear tests conducted on laboratory reconstituted samples. Field trials have been conducted in road embankment and slope protection with vetiver at different sites. During the time of vetiver root growth the soil protection has been accomplished by geo-jute. As the geo-jute degrades with time, vetiver roots grow and take over the function of geo-jutes. Slope stability analyses showed that vegetation increase the factor of safety significantly.

Keywords: Erosion, geo-jute, green technology, vegetation.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1078837

References:

[1] M. A. Rajib, M. M. Rahman, and A. Edward,"Global warming in Bangladesh perspective: Temperature projections upto 2100," Proceedings of the Global Conference on Global Warming, 2011.
[2] T. N. Krishnamurti, R. Correa-Torres, M. Latif, and G. Daughenbaugh, "The impact of current and possibly future SST anomalies on the frequency of Atlantic hurricanes." Tellus, 50A, pp. 186-210,1998.
[3] M. S. Rana, K. Gunasekara, M. K. Hazarika, L. Samarakoonand, and M. Siddiquee, "Application of remote sensing and GIS for cyclone disaster management in coastal area: A case study at Barguna district, Bangladesh." International Archives of the Photogrammetry, Remote Sensing and Spatial Information Science, Volume XXXVIII, Part 8, Kyoto Japan, pp. 122-126, 2010.
[4] M. N. Islam, "Embankment Erosion Control: Towards Cheap and Simple Practical Solutions for Bangladesh", Coastal Embankment Rehabilitation Project, South Khulshi, Chittagong, Bangladesh.
[5] M. S. Islam, Arifuzzaman and S. Nasrin,"In-situ shear strength of vetiver grass rooted soil," Proc. of Bangladesh Geotechnical Conf. 2010: Natural Hazards and Countermeasure in Geotechnical Engineering, Dhaka, Bangladesh, pp.274-279, 2010.
[6] http://www.banglapedia.org/httpdocs/HT/S_0459.HTM, Date of visit: 09/04/2012.
[7] P. N. Truong, I. Gordon, and D. Baker, "Tolerance of vetiver grass to some adverse soil conditions," Proc. First Int. Vetiver Conf., Thailand, 1996.
[8] P. N. Truong, and D. Baker, "Vetiver grass system for environmental protection," Technical Bulletin No. 1998/1, Pacific Rim Vetiver Network Office of the Royal Development Projects Board, Bangkok, Thailand, 1998.
[9] C. Ke, Z. Feng, X. Wu, and F. Tu,"Design principles and engineering samples of applying vetiver eco-engineering technology for steep slope and riverbank stabilization," Proc., 3rd Int. Conf. on Vetiver (ICV-3), Guangzhou, China, pp. 349-357, 2003.
[10] M. M. Rahman, M. A. Islam, S. H. Rashid, M. M. K. Mia, and M. H. Rahman, "Study on the distribution and potential of vetiver grass in Bangladesh," Bangladesh Journal of Plant Taxonomy, Vol. 3(2), 1996, pp. 1-16.
[11] J. Hellin and M. J. Haigh, "Better land husbandry in Honduras: towards the new paradigm in conserving soil, water and productivity", Land Deg Dev 13,John Wiley & sons, Ltd., pp. 233-250, 2002.
[12] D. Hengchaovanich, "Vetiver grass for slope stabilization and erosion control." Tech. Bull. No. 1998/2, PRVN/ORDPB, Bangkok, Thailand, 1998.
[13] J. Thomas, N. A. Talukdaer, and E. Akand, "Vetiver grass for erosion control, around the world," published by Dampara Water Management Project, A Joint Project by Bangladesh Water Development Board and Canadian International Development Agency, 2002.
[14] M. S. Islam, Arifuzzaman, H. M. Shahin, and S. Nasrin, "Effectiveness of vetiver root in embankment slope protection: Bangladesh Perspective", Int. J. of Geotech. Engg., 2013(in press).
[15] ASTM, Annual Book of ASTM Standards, Vol.04.08, Soil and Rock; Building stones; Geotextiles, 1989.
[16] I. Khan and M. N. Sakib, "Determination of absorption capacity of geojute" Undergraduate Thesis, Department of Civil Enginnering, Bangladesh University of Enginnering and Technology, Dhaka, Bangladesh, 2012.
[17] A. W. Bishop, "The use of slip circles in the stability analysis of slopes", Geotechnique, Vol. 5, No. 1, 1955.
[18] N. J. Coppin, and I. G. Richards (eds), "Use of Vegetation in Civil Engineering." Construction Industry Research Information Association/Butterworths, London, pp. 45-50, 1990.
[19] T. Sanyal, "Jute Geotextile in Erosion Control & Strengthening of Sub- Grades - Two Case Studies", Geosynthetics-Recent Development-s, Publication No. 298 of Indian chapter of International Geosynthetics Society & CBIP, 2006.
[20] Local Government Engineering Department (LGED), Schedule Rate Book, 2011.
[21] Bangladesh Water Development Board (BWDB), Schedule Rate Book: CC Block & Geo-textile Rate, 2011.