Slope Stability Assessment of The Crocker Formation in Telipok, Sabah

Writers : Ismail Abd. Rahim, Sanudin Haji Tahir, Baba Musta & Rodeano Roslee

Date : 21-22 Nov 2006

Publisher : Southeast Asian Natural Resources And Environmental Management (SANREM 2006)

Location : Kota Kinabalu

Abstract :

Crocker Formation is a flysch deposits and classified as tabular block type. Rock cut slope instability in the Crocker Formation has been affecting the engineering design, controlled by discontinuity as well as other factors and proven by the occurrences of varied rock falls block size from a cubic millimeter to more then a cubic meter. Orientation data have been obtained by discontinuity survey in four cut slope exposures using scan line method. Stereonet analysis has been performed to these data in the commercial computer software packages of lower hemisphere spherical projection. The pole plot method and Markland test has been used to determine the discontinuity sets and mode of failures, respectively. As results, there are four sets of major discontinuity in station 1B, five sets in station 2A and 2B and six sets in station 1A, which are related to the regional tectonic history. The bedding plane has been identified as the most critical plane as well as southwestern dipping (133/53), southern dipping (83-111/70-75) and northeastern dipping (287o-293o/43o-74o) joints. These critical discontinuity planes is also have an important influence on rock cut slope stability in the Crocker Formation which potential for generating wedge failure and few possibilities for toppling and planar failures.