FOCUS AREAS
Rain induced landslides causing widespread property damage and loss of lives is a major challenge faced by the Sri Lankan Geotechnical Engineers. During the last ten years it has become evident that the most devastating landslide events tend to occur as a result of comparatively short duration, high intensity rainfalls in addition to the previously identified lower intensity prolonged rainfalls.
Rain induced landslides occur in 13 major districts in the central highland and south western parts of the country which occupies about 20-30% of the total land area and affects 30-38% of total population (6-7.6 Million). The increase of the number of landslides and the affected areas over the years could be attributed to; adverse changes in the land use pattern, non-engineered constructions, neglect of maintenance and changes in the climate pattern causing high intensity rainfalls.
Threshold rainfall intensities and durations leading to landslides are currently decided based on past experience. However, with the changes discussed above now it is apparent that more site-specific threshold rainfall intensities should be established for critical slopes in the country. Hence studies were done to model the process of infiltration and study the changes taking place in the pore pressure regime leading to failure. Further studies are conducted to establish the soil characteristics necessary for the modelling.
Effectiveness of processes such as; surface and sub surface drainage, use of vegetation and use of structural solutions to enhance the stability are also being studied. Increasing attention is paid to find out solutions that blend nicely with the natural environment.
PUBLICATIONS
- Mihira Lakruwan SOAD, Kulathilaka SAS (2020), Economizing Soil Nailing Design by Drainage Improvement - Case History at Ginigathhena, Paper accepted for publication at the World Landslide Forum, Kyoto, Japan 2020
- Idirimanna IAND, Kulathilaka SAS (2019), Back analysis of slope failure at Welipenna, Southern Expressway, Geotechnical Journal, Journal of the Sri Lankan Geotechnical Society.
- Karunarathna SWBS, Dahanayaka DRIN, Maduranga HR and Nawagamuwa UP (2019) Geotechnical Effects on Ground due to Sudden Water Ingress of Uma Oya Head Raise Tunnel 10th Annual NBRO Symposium, 17-18 December 2019, PP 297-304
- Ganepola GAC, Dayarathna PGNN, Kankanamge L, Arambepola NMSI, Nawagamuwa UP, Basnayake S (2019), Guidance Document on Use of Nature-based Solutions for Landslide Risk Reduction, 10th Annual NBRO Symposium, 17-18 December 2019, PP 380-389
- Ranasinghe AKRN, Bandara R, Puswewala UGA, Dammalage TL (2019), Efficacy of using radar derived factors in landslide susceptibility analysis: case study of Koslanda, Sri Lanka, Natural Hazards and Earth System Sciences, Vol. 19, pp. 1881-1893.
- Jayasinghe MTR, Jayasinghe C, Kariyawasam KKDKD, De Silva LIN (2018) Semi-Tiered Housing for Laterite Earth Sloping Lands—A Sustainable Solution with Alternative Materials and Methods. Journal of Green Building: Winter 2018, Vol. 13, No. 1, pp. 56-72.
- Rajeevkaran P, Kulathilaka SAS, Influence of Matric Suction on Pullout Resistance of Soil Nails, Annual Sessions of the Institution of Engineers, Sri Lanka, pp 111-119.
- Jayakody SHS, Galhena GDWN, Karunawardena AW, Kulathilaka SAS (2018), Stability Analysis of the Failure at Meethotamulla Waste Fill, Annual Sessions of the Institution of Engineers, Sri Lanka, pp 121-128.
- Kankanamge L, Rajamanthri K, Kulathilaka SAS, Dissanayaka DMDS (2018), Analysis of a Slope Triggered by Rainfall Infiltration: A Case Study on Ihalakotte Earthslip. 9th Annual National Building Research Organization (NBRO) Symposium, Innovations for build back better, Sri Lanka, pp. 268 -276.
- Kumara GDD, Jayathissa HAG, Nawagamuwa UP (2018), Determination of rainfall thresholds for landladies in Sri Lanka, 9th Annual NBRO Symposium, 18-19 December 2018, PP55-63
- Mampitiyaarachchi CT, Bandara RMS, Bandara KN, Nawagamuwa UP (2018), Study on unstable locations along upcountry railway line, 9th Annual NBRO Symposium, 18-19 December 2018, PP105-112
- Nawagamuwa UP, Perera LP (2017), Recommending rainfall thresholds for landslides in Sri Lanka, Proceedings of the 4th World Landslide Forum, Ljubljana, Slovenia, May-June 2017.
- Ranasinghe AKRN, Sirisena PMTS, Dammalage TL, Puswewala UGA (2016), Integration of Radar and Optical Remote Sensing for landslide detection – A case study of Meeriyabedda landslide in Sri Lanka, Proceedings, 37th Asian Conference of Remote Sensing, Colombo, Sri Lanka, Session TS20.
- Ranasinghe AKRN, Sirisena PMTS, Dammalage TL, Puswewala UGA (2016), Terrain failure and debris flow susceptibility analysis in GIS Environment – A case study of Koslanda area in Sri Lanka, Proceedings, 12th International Conference of International Institute for Infrastructure Resilience and Reconstruction (IIIRR), Kandy, Sri Lanka, Session IIIRR/028 (Disaster Resilience).
- Ranasinghe AKRN, Munasinghe DS, Dammalage TL, Puswewala UGA (2016), Landslide prediction using Remote Sensing and GIS – A case study of Koslanda, Sri Lanka, Proceedings, 37th Asian Conference of Remote Sensing, Colombo, Sri Lanka, Session TS13.
- Dharmasena RKN, Kulathilaka SAS (2015), Stabilization of Cut Slopes in Highways by Surface drainage and Vegetation, International Conference on Geotechnical Engineering (ICGE-Colombo-2015), Sri Lanka.
- Dharmasena UKNP, Bandara KN, Karunawardena WA, Kulathilaka SAS (2015), Back Analysis and Rectification of a Failed Cut Slope in the Southern Expressway, International Conference on Geotechnical Engineering (ICGE-Colombo-2015), Sri Lanka.
- Ganeshalingam C, Kulathilaka SAS (2015), Shear Strength Characteristics of Unsaturated Residual Soils, Civil Engineering Research Symposium (CERS) of Department of Civil Engineering, University of Moratuwa.
- Ranasinghe AKRN, Silva GBAI, Dammalage TL, Welikanna DR, Puswewala UGA (2015), Detection of Meeriyabedda Landslides from high resolution optical satellite data, Proceedings, 36th Asian Conference of Remote Sensing, Manila, Philipppines, pp. TH4.5.2.