Challenges of excavation by ripping works in weathered sedimentary zone

Ripping is a method of loosening rock during excavation using steel tynes attached to the rear of bulldozers. The tynes are lowered into the ground as the bulldozer moves forward and soil or blocks of rock are displaced by the tynes. In tropical region where thick profile of weathered zone can be encountered, ripping work is always accepted as the limit of mechanical breaking before blasting works is preferred due to the economical reason. However, as we know, the nature of rock type and its weathering profile play a very significant role in evaluating the excavation assessment. Great challenges in ripping work can be expected in sedimentary zone where the occurrence of discontinuity such as bedding thickness, folding, foliation and the inhomogeneity of rock can greatly influences its excavatability. This paper aims to highlight some of the problems that arise in weathered sedimentary area as what have been experienced in Malaysia during the surface excavation works.