Pengaruh Pelapukan Lapisan Batuan Terhadap Stabilitas Lereng

Adolf Situmorang; Kusrin Kusrin; Ngudi Hari Christa; Yesina Intan Pratiwi; Galih Widyarini; Kukuh Wisnuaji Widiatmoko

doi:10.29103/tj.v12i2.707

Pengaruh Pelapukan Lapisan Batuan Terhadap Stabilitas Lereng

Adolf Situmorang, Kusrin Kusrin, Ngudi Hari Christa, Yesina Intan Pratiwi, Galih Widyarini, Kukuh Wisnuaji Widiatmoko

Abstract

Abstrak

Longsor merupakan suatu proses perpindahan massa batuan atau tanah akibat pengaruh gravitasi sebagai respon terhadap aktivitas alam yang menyebabkan kerusakan morfologi permukaan lereng, dan longsor yang terjadi di Wonogiri kemungkinan karena pelapukan lapisan batuan akibat curah hujan yang sering terjadi di aera tersebut. Penelitian ini dilakukan dengan tahapan pengambilan sampel batuan, pengukuran dan pengumpulan data sekunder. Klasifikasi batuan menggunakan parameter RQD, RMR dan Q-system untuk mengetahui karakteristik batuan. Hasil dari klasifikasi tersebut menunjukkan bahwa lapisan batuan di lokasi longsor masuk dalam kategori sedang hingga sangat rentan mengalami pelapukan. Dengan mempertimbangkan siklus curah hujan dan jumlah hujan dalam hari yang dihitung dalam satu tahun diketahui ada pengurangan kekuatan batuan berdasarkan penelitian terdahulu. Hasil analisa metode element hingga menunjukkan terjadi pengurangan kekuatan batuan berdasarkan parameter geser yang berakibat pada stablititas lereng batuan tersebut, dan pada tahun ke-10 diindikasikan nilai Safety Factor (SF) <1,3.

Kata kunci: Kuat geser, siklus basah-kering, batuan

Abstract

Landslide is a process of mass transfer of rock or soil due to the influence of gravity in response to natural activities that cause damage to the surface morphology of the slopes, and the landslide that occurred in Wonogiri was probably due to weathering of rock layers due to frequent rainfall in the area. This research was conducted with the stages of taking rock samples, measuring and collecting secondary data. Rock classification uses RQD, RMR and Q-system parameters to determine rock characteristics. The results of the classification indicate that the rock layers at the landslide location are in the moderate to very vulnerable category to weathering. By considering the rainfall cycle and the amount of rain in days calculated in one year, it is known that there is a reduction in rock strength based on previous research. The results of the finite element method analysis showed that there was a reduction in rock strength based on shear parameters which resulted in the stability of the rock slopes, and 10th year indicated the value of Safety Factor (SF) <1.3.

Keywords: Landslide, wet-dry cycle, rock

Keywords

Landslide, wet-dry cycle, rock

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DOI: http://dx.doi.org/10.29103/tj.v12i2.707