ANALYSIS OF THE EFFECT GROUNDWATER LEVEL FLUCTUATION ON SLOPE STABILITY IN THE COAL MINING PLAN

A. N. Dwi; M. Asof; D. Purbasari

doi:10.36706/jp.v8i4.2467

A. N. Dwi Universitas Sriwijaya
M. Asof Universitas Sriwijaya
D. Purbasari Universitas Sriwijaya

DOI: https://doi.org/10.36706/jp.v8i4.2467

Keywords: slope stability, ground water level, observation well, morgenstern price, casagrande piezometer

Abstract

Based on geotechnical drilling activities carried out in the PT Battoman Coal mining plan area, it is known that the slope material is dominated by claystone. According to Chen (1975), claystone can be expansive when exposed to water, disrupting slope stability. The presence of the Sungai Putih tributary in the mining plan area can also affect slope stability. This research aims to analyze the influence of groundwater level fluctuations on slope stability in the PT Battoman Coal mining plan area based on actual conditions as a result of the research. Ground water level observations and measurements were conducted using the Casagrande piezometer method and observation wells in the high wall area. Slope stability analysis was carried out using the software Rocscience Slide V.6 using the Morgenstern Price method and the Mohr-Coulomb failure type by simulating slopes in actual conditions, the results of the highest and lowest groundwater measurements in the period September to October 2023, namely 4,26 meters and 28,45 meters from the ground surface. The analysis was carried out in pseudo-static conditions using mining area seismicity factors based on the Indonesian Seismic Zone Map according to the Ministry of PUPR in 2017. Overall slope area high walls in cross sections A-A' and B-B' are included in the critical to stable category with FK values between 0,901 to 1,782. Recommendation of overall slope designed by Kepmen ESDM 1827K/MEM/2018 so that it is obtained overall slope which is stable in saturated conditions with FK values between 1,176 to 1,245.

References

[1] Arif, I. (2021). Geoteknik Tambang: Mewujudkan Produksi Tambang Yang Berkelanjutan Dengan Menjaga Kestabilan Lereng, Edisi Kedua. Jakarta: Pt Gramedia Pustaka Utama.

[2] Frans, J. S., & Nurfalaq, M. H. (2019). Studi Geoteknik Pengaruh Muka Air Tanah Terhadap Kestabilan Lereng Tambang Batubara. Jurnal Perhapi, 1(1), 12-21.

[3] Adi, J. E. (2024). Pengaruh Serbuk Gypsum terhadap Indeks Plastisitas dan Parameter Geser Tanah Berbutir Halus. Thesis, Faculty of Engineering: Atma Jaya University Yogyakarta.

[4] Vickyla, M., Sophian, I., & Muslim, D. (2019). “Pengaruh Muka Air Tanah Terhadap Kestabilan Lereng Tambang X. Geoscience Journal, 191-198.

[5] Meriza, M. (2021). Analisis Pengaruh Muka Air Tanah Terhadap Kestabilan Lereng Pada Tambang Batubara Pt. Bukit Asam, Tbk. Teknik Pertambangan. Thesis, Faculty of Mineral Technology: National Development University "Veteran" Yogyakarta.

[6] Pupr, K. (2017). Modul Instrumentasi Bendungan Urugan Pelatihan Perencanaan Bendungan Tingkat Dasar. Bandung: Pusat Pendidikan Dan Pelatihan Sumber Daya Air Dan Konstruksi.

[7] Kepmen Menteri Esdm 1827K Tahun 2018 Tentang Pedoman Pelaksanaan Kaidah Pertambangan Yang Baik. (N.D.).

[8] Wiradani, P. K., & Heriyadi, B. (N.D.). Analisis Probabilitas Kelongsoran Menggunakan Metode Monte Carlo pada Highwall Pit Sb-Ii Bk-14 PT Trubaindo Coal Mining, Site Melak, Kabupaten Kutai Barat, Kalimantan Timur, Bina Tambang Journal, 1617.

[9] Handayani, T., Wulandari, S., & Wulan, A. (2014). Pengaruh Muka Tanah terhadap Stabilitas Lereng Menggunakan Geoslope/W 7.12. Prosiding Seminar Ilmiah Nasional Komputer Dan Sistem Intelejen (Kommit 2014), Depok: Fakultas Teknik Sipil dan Perencanaan. Faculty of Civil Engineering and Planning.

[10] Hasan, B. M., & Heriyadi, B. (N.D.). Analisis Balik Kestabilan Lereng Tambang Batubara Pit Rts-C Sisi Barat Wup Roto-Samurangau Pt. Kideco Jaya Agung, Kecamatan Batu Sopang, Kabupaten Paser, Provinsi Kalimantan Timur. Bina Tambang Journal, 74-84.