Effects of Moisture Content on Soil Strength around Kampung Lohan, Ranau, Sabah

Ranau landslides mostly occur due to moisture content and soil properties. In this study, the effect of moisture content on soil strength was analyzed using Unconfined Compression Test. Five samples were taken around Kampung Lohan which two are Crocker Formation soil samples (K1 and K3) and three were ultrabasic soil samples (K2, K4 and K5). The term ‘Decrement Difference of Unconfined Compression Strength’ is used to define the percentage drop of shear strength difference of the manipulated oversaturated samples to its shear strength at optimum moisture. The highest drop was 90.18% in clayey soil (K2) because it is rich in minerals that are able to absorb and adsorb water while lowest drop of 50.32% by sandy clay with silt (K1). Thus, sand rich soils of Crocker Formation have higher compression strength than ultrabasic soils with expansive clay while the moisture effect on soil is directly proportional to thecompression strength.