Browsing by Author "Wijewickrama, MIDH"

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item: Article-Abstract
Matale ground subsidence and overlooked construction basics
Nawagamuwa, UP; Wijewickrama, MIDH; Sugathapala, K; Karunawardena, WA; Bandara, RMS
Since few years back, there has been several cases reported on construction failures and sink holes in Matale due to a possible ground subsidence affecting human settlements in the region. Villagers have been living with a belief of an under ground river flowing in some areas of Matale. National Building Research Organization (NBRO) has been consulted in investigating the existing situation. Garnet silimanite biotite gneiss and Crystalline Limestone are found to be major rock types in the said area confirming a karstic geomorphology with caverns spreaded in a vast area. With the help of drilling and tube well records, and geophysical survey results, hazard zonation mapping has been initiated. The hazard zonation map shows nearly 2900 houses from 24 GN divisions found to be affected in a risk scale from high to very low. A human settlement survey was carried among 89 houses of severely affected houses to investigate the extent of the damages and also to summarise civil engineering technologies adopted in their house construction. It was found that the construction basics had been overlooked due to lack of awareness among the residents in the said vulnerable condition prevailing in the area. This paper summarises basic geology of the area, mapping procedure and neglected construction basics which are vital factors that should be considered when human settlements found in problematic geological areas.
item: Conference-Full-text
Structural mitigation for stabilizing rock slope failure at Peradeniya on Colombo- Kandy Main Road: geotechnical and constructional aspects
(Department of Earth Resources Engineering, 2010-09) Premathilaka, KKW; Munasinghe, MPNJ; Kasthurirathna, KANS; Kumara, ALDP; Senapathi, LR; Abeysinghe, AMKB; Premasiri, HMR; Chaminda, SP; Puswewala, UGA; Wijewickrama, MIDH; Ratnayake, NP; Abeysinghe, AMKB; Premasiri, HMR; Karunaratne, S
Rock slope failure at Kandy -Colombo highway near Peradeniya town has been identified as a major threat to the highway as well as the people and properties of the vicinity. This study proposes a permanent mitigation plan for the rock slope failures at this site. Study was initiated with the analysis of similar case studies and field studies on the site area and mitigation options. Two level surveys were carried out to collect topographical data for preparation of a 3D model of the slope. Material identification was done by using particle size analysis and plasticity tests; direct shear tests were carried out to determine the friction angle, cohesion and density of the material. Mitigation plan was designed according to the site conditions. The design was analysed for nine sections on the slope for its stability with the test results by using Geo-studio 2004 software. Reinforcements were proposed to improve the stability whenever needed. An appropriate drainage system was also designed having analysed the past rain fall data of the area. The proposed mitigation plan in this study is a highly stable, safe, trouble-free and economically feasible one, and that can be implemented on this site.