General geology and relationship between particle size, plasticity index and clay mineral content with slope failure at Kampung Bukit Pak Abu, Dabong, Kelantan

Slope failures are caused by many factors in which the strength of the soil is disturbed. The relationship between particle size, plasticity index and clay mineral is investigated in this research. The study area has a longitude between 102° 3‘l5.99"E to 102° 7'27.31"E and latitude between 5°22'39.36"N to 5°l9'l7.99"N, located at Kampung Bukit Pak. Abu, Dabong, Jeli, Kelantan,surrounded by hilly region. The objective is to conduct a detailed geological mapping and to investigate the effect of plasticity index on slope failure and study the influence of clay mineral towards slope failure. The lithologies found at the study area are interbedded siltstone and shale, and phyllite. A minor fault was located and 10 joint sets were obtained. Sieve analysis was conducted to determine the particle size distribution, liquid limit and plastic limit was determinedto obtain the plasticity index, and X-Ray diffraction is conducted to detennine the presence of clay mineral. Types of clay mineral presence are kaolinite, illite and montmorillonite. The average plasticity index is at the slightly-plastic range which is 3-14. Grain size distribution shows that the soils in that area is poorly-graded soils.