Landslide Analysis in Bojongkondang, Cihanjuang, Cimanggung, Sumedang Regency, West Java Antonina Pri MARTIRENI(a*), Koko HERMAWAN(a), Okta FAJAR(a) ,Adrin TOHARI(a), Eko SOEBOWO(a)
Research Center for Geotechnology, Indonesian Institute of Sciences, Bandung, Indonesia.
Jl. Cisitu, Sangkuriang Bandung 40135
antonina.martireni84[at]gmail.com
Abstract
Landslide is the movement of land due to disruption of its natural balance. Landslide is influenced by several factors, those are controlling factors and triggering factors. The purpose of this study was to examine the effect of the stability of the former embankment slopes into settlements. The load caused by settlements in weak rock conditions is also the cause of the landslides. To analyse slope stability and geotechnical properties along the landslide, 3 points of undisturb (Shelby tube) sample data were taken, rainfall observations, aerial photographs, rock lithology and morphological forms were taken. From the results of observations of rainfall in the last 10 years, it indicated that in January-May 2021 it was 160 mm/day with a very heavy category. The Cimanggung landslide caused 34 houses were damaged. Changes in land use also occurred from 2015 to 2020. The change in elevation due to landslide was ± 4 m. 3D modelling is performed by comparing the results of aerial photographs and Landsat images obtained the landslide volume of 13,180 m3. Geologically, the landslide areas are composed of weathered volcanic breccia rocks, tuffaceous sand, lapilli (Qyu). In the landslide zone there are no traces of water seepage or ground water were found. This indicates that the groundwater table is quite deep. The morphology of the landslide area is hill intrusion slopes in the southern part which forms a valley to the southwest with a slope of ± 25 - 35 degree. The landslide had dimensions of ± 45 m width, ± 143 m length, and ± 30 m height. The height of the landslide area is 690 - 730 masl. The landslide zone is 264 degree from the north with an area of 5.252 m2. The calculation of the slope safety factor was analysed using slide software v5.0.
