Geological Behavior (GBR)

This study focused on the discontinuity survey and mode of rock slope failure along the Bundu Tuhan to Kundasang road, approximately 84th km to 96th km from Kota Kinabalu city, Sabah. The area is underlain by the Trusmadi Formation (Palaeocene to Eocene age), the Crocker Formation (Late Eocene to Early Miocene age) and the Pinousuk Gravels (Upper Pleistocene to Holocene age). These rock units show numerous lineaments with complex structural styles developed during several regional Tertiary tectonic activities. The tectonic complexities reduced the physical and engineering properties of the rock masses and produced intensive displacements and discontinuities among the strata, resulting in high degree of weathering process and instability. The weathered materials are unstable and may cause sliding and falling induced by high pore pressure subjected by both shallow and deep hydrodynamic processes. In this study, a total of ten (10) selected critical rock slopes failure was studied. Kinematics slope stability analyses indicates that the variable potential of circular, planar, wedge and toppling failures modes as well as the combination of more than one mode of aforementioned failure. The rock properties of ten (10) rock samples indicated that the point load strength index ranges from 0.33 MPa to 0.52 MPa (moderately week) and the uniaxial compressive strength range from 7.81 MPa to 12.57 MPa (moderately week). Development planning has to consider the hazard and environmental management program. This engineering geological study may play a vital role in rock slope stability assessment to ensure the public safety.