Comparative Study On Permeability Characteristics Of Kathmandu Valley Soils

Abstract

This study investigates the permeability characteristics of the different nine soils from the Kathmandu i.e. from Kalanki, Champi, Matatirtha, Thimi, Kamerotar, Luvu, sand of Bagmati, sand of Manohara and sand from Bungmati. Visual inspections, Grain size distributions, Atterberg limits, Specific gravity, Permeability test of soils are carried out. The digitization of the test result from the literature of Lambe and Whitman is done with the aid of Plot digitizer software. From the result of classification of soil as per USCS Sand from Manohara, Bagmati and from Bungmati are classified as SP. Kalanki and Luvu soil as CL, Matatirtha soil as CL-ML, Thimi soil as ML and OL, Kamerotar and Champi soil as ML. Result of study on the permeability characteristics of the Kathmandu soil, it is found that as the void ratio of soil increases the coefficient of the permeability increases and vice versa. The relation between the void ratio and the coefficient of permeability is found to be almost straight for all soil. The coefficients of permeability of Kathmandu valley soil are found within range of 10-2 cm/sec to 10-7 cm/sec. As per Terzaghi and Peck (1967) classification soils from Kathmandu are classified as soil having very low permeability to medium permeability. Further, comparison between test result of my investigation and literature test result it shows that permeability of soils from Thimi, Champi, Matatirtha, Kalanki, Kamerotar and Luvu lies between the permeability characteristics of silt of Boston to Sand from Dike. The Champi soil permeability characteristic is similar to that of Silt- North Carolina. This research works deals with simple observation of K values of soils at different location of Kathmandu, the difference between K values for these soils are mainly due to particle size and somehow affected by composition, structure and shape of particles.