Influence of Soil Physical Properties on Rainfall Induced Landslide Susceptible Areas along Cagayan de Oro-Bukidnon-Davao City Route Corridor, Philippines

The Cagayan de Oro (CDO)-Bukidnon-Davao City route corridor plays a vital role in the movement of commerce and trade in the region by linking the two major economic centers of Mindanao, the CDO and Davao Cities. However, this national highway traverses the mountainous ranges of Bukidnon which is prone to rainfall-induced landslides. This study aims to characterize the grain size distribution (GSD), soil consistency (Atterberg Limits) and the influence of moisture content on the yield stress of rainfall-induced landslide prone areas along the route corridor. Majority of the landslide prone areas are dominated by high clay content characterized by high plasticity and high potential to swell (PI > 23 and LL > 50). The yield stress of slip prone clayey soil areas along the CDO-Bukidnon-Davao city highway soil decreased either linearly or exponentially with increasing moisture content. All samples showed critical moisture content which ranged from 60 to 80 % in which a sudden drop of the yield stress was observed. Hence, this study could provide necessary information for various government agencies to come up with pro-active implementation of landslide risk mitigation and management so that cost, hassles and exposure to such risks may be reduced.

 

Keywords: Atterberg Limits, clayey soil, Grain Size Distribution (GSD), Yield Stress, Soil Moisture