General geology and slope stability assessment of cut rock slope in Paloh, Gua Musang

Rock slopes with high frequency of joints and fractures might pose danger to human especially those close to the roads and residential areas. Slope stability analysis was conducted on three rock cut slopes nearby the Gua Musang Kota Bharu Highway in the study area. The objectives of this research are to produce geological map of study area, identify the strength of intact rock materials using point load test, to investigate the condition of rock mass within the slopes using rock mass rating and to determine the types of slope failure using kinematic analysis. Geology of the study area also been identified before conducting slope stability analysis. Quartzite, siltstone and limestone unit were found in the study area. The geological ages of these units ranged from Permian to Triassic, where quartzite unit represents the oldest unit and limestone represents the youngest unit. Rose diagrams showed that oblique-slip fault was present in the study area. The methods used in slope stability assessment include rock mass rating and kinematic analysis. Point load test were used to convert the related results into UCS to be used in RMR, discontinuity survey also had been conducted to be used in RMR and kinematic analysis. Rock masses on slope 1, 2 and 3 has point-load strength indexes of 0.23, 0.09 and 0.25 respectively. These values were converted into UCS by using conversion factor of 24. RMR also classified rocks at slope 1 and 2 were good rock (Class ll) whereas rock at slope 3 was poor rock (Class IV). Discontinuity survey found that there are three joint sets were presence in each slope 1 and 3 whereas two joint sets found in slope 2. However, Kinematic analysis shows that all of these slopes were stable.