Empirical and numerical method approaches in determining the value of rock slope safety factors at JJLS Gunung Kidul, Yogyakarta

Abstract

Limestone is one of the most numerous sedimentary rock groups, limestone consists of non-clastic limestone and clastic limestone. The research slope is on the Southern Cross Road (JJLS) in Gunung Kidul LOT 4 (Legundi-Plajan) which has  length of 4.7 KM, where the rock slopes are in a location that is busy with traffic and close to where residents live. The purpose of this study is to determine the slope safety value with empirical and numerical approaches using RMR and RS 2. In this study, there are several types of data used, namely field data including megascopic rock descriptions at the research location, and laboratory data, namely UCS data. From this study, it was found that the formation of slopes 1 and 2 was included in the category of rock mass quality, while slope 3 was good. RMR values that are not much different do not make the slopes have the same weighting, because the slope geometry and the discontinuity geometry plane. Based on the value of slope stability using phase 2 software to get stable FK, there is a significant difference between slope 1,2 and slope 3, where the difference in safety factors can be influenced by discontinuity conditions, discontinuity orientation and activities around the slope.