Browsing by Author "Lakshamana, NWH"

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item: Conference-Abstract
Effect of relict joint in rain induced slope failures in residual soil
(2011) Kulathilaka, SAS; Kumarasinghe, R; Lakshamana, NWH; Neethimappiriya, T
Rain induced slope failures i s a common geotechnical hazards in most parts of the world. Particularly in the tropicaI regions, which are covered with residual soil, the temporal frequency of rainfall induced slope failures is very high. These problems are encountered in the construction of highway with the very high cut slopes. So the special focus should consider in the highway construction. Residual soils are formed due to weathering of rocks. The residual soils are heterogeneous due to variable weathering of the jointed mass rock. Joints are formed due to decomposition of rock Due to the presence of relic joints, the behavior of the residual soil is quite complex. Generally the ground water table is low during the dry season and these soils are in an unsaturated state. The shear strength of a soil is enhanced by matric suction. As a result of infdtration of rain water, the matric suction will be destroyed and ground water table rise.. Due to the loss of matric suction the slope failures can induce. This aspect is studied in this research with the infiltration model by using SEEPW, SLOPE Wsoft ware.
item: Conference-Full-text
Effect of relict joints in rain induced slope failures in residual soil
(Department of Civil Engineering, University of Moratuwa, 2011-12) Tharmalingam, N; Lakshamana, NWH; Kumarasinghe, RDTB; Kulathilaka, SAS; Ratnayake, N
Rain inducted slope failures are a common geotechnical hazard in the most parts of the world. particularly in the tropical reagon, which are covered with residual, soil, the temporal frequency of rainfall inducted slope failures is very high. These problems are encountered frequently in the construction of highway where very high cuts are made in the slopes. Residual soils are formed due to weathering of rocks and the joints remain as relict joint even after the weathering process. The residual soils are heterogeneous due to variable weathering of the jointed mass rock. Generally the ground water table is low during the dry season and these soils are in an unsaturated state with negative pore water pressure above the water table. As a result of infiltration of rain water, the matric suction will be distroued and ground water table will rise. Relict joints present in the system will further complicate the pattern of infiltration. Changes in the pore pressure regime due to infiltration and its effect on safety was studied in a previous research. The objective of this research is to investigate the effects of different systems of relict joints in the infiltration and stability. This aspect was studied in this research using SEEPW, SLOPEW software.