Rekayasa Lereng Andesit Menggunakan Metode Finite-Element

Ruslan Loilatu; Andy Erwin Wijaya

Ruslan Loilatu Institut Teknologi Nasional Yogyakarta
Andy Erwin Wijaya Institut Teknologi Nasional Yogyakarta

Abstract

Geotechnical study data collection includes geotechnical mapping, observations of landslide models that can occur, and sampling for physical and mechanical properties testing. The geotechnical study carried out is by analyzing slides on production slopes, the analytical method used in the analysis of landslides on slopes is the kinematic method, analysis with this method uses rock mass parameters, discontinuity planes, and production slope geometry as input. From the results of avalanche analysis using the kinematic method, it was found that the landslide that has the potential to occur is a field avalanche of 47,50%.The overall slope stability analysis using the Finite Element Method (FEM) shows the overall slope is in a stable condition seen from the value of the Safety Factor (FK) which is 1, 26. For single slope stability analysis, the slope is modeled with three variations of slope and three variations of height to determine the minimum limit for optimal slope geometry, for slopes with a slope of 50o the SRF value obtained from the modeling results > 1.25 which shows the slope is in stable condition, the slope is stable. has a safety factor of <1.25 (unstable), namely a slope with a slope of 70o which indicates that if the slope is made higher, a landslide can occur on the mine slope.For slopes with optimal conditions compared to the other two angle variations, slopes with a slope of 50o and a maximum height of 10 m with an SRF of > 1.25 which can be used as optimal slope recommendations, slopes with this slope if modeled with several variations in height, namely 5 m has an SRF of 2,02 , a height of 10 m has an SRF of 1.48, and a height of 15 m has an SRF of 1.28, which shows three variations in height using a slope of 50o have an FK value > 1.25, whereas if the height is made to exceed the height limit 10 m, the slope will have the potential for landslides.

Keyword : Geotechnical Studies, Overall Slope Stability, Safety Factors, FEM, Actual Slope Geometry.

References

A. Irwandy, “Geoteknik Tambang: Mewujudkan Produksi Tambang yang Berkelanjutan dengan Menjaga Kestabilan Lereng,” Jakarta : Gramedia Pustaka Utama, 2016.

M. A. Azizi, S. Kramadibrata, R. K. Wattimena, I. D. Sidi, S. Basuki, dan Suhedi, “Aplikasi Probabilistik Untuk Analisis Kestabilan Lereng Tunggal (Studi Kasus di PT Tambang Batubara Bukit Asam Tbk. Tanjung Enim, Sumatera Selatan),” Prosiding TPT XX PERHAPI Mataram 10-12 Oktober 2011, 2011, pp. 511-521.

Brazilian, 1999 dalam Made, dkk, “Mekanika Batuan” Bandung : ITB, 2014.

Badan Pusat Statistik Kabupaten Cianjur. Kabupaten Cianjur dalam Angka. Cianjur: BPS Kab. Cianjur, 2018.

Badan Informasi Geospasial (BIS), “Demnas Kabupaten Cianjur,” 2021. [online]. available at: http://geospasial.co.id. [diakses: 16 September 2021].

J. E. Bowles, “Sifat-Sifat Fisis dan Geoteknis Tanah,” Jakarta: Erlangga, 1998.

D. Trisnawati, “Kajian Kekuatan Tanah dan Kestabilan Tubuh Tanggul Pada Rencana Tanggul Wedok Lumpur Sidoarjo,” Repository Teknik Geologi Undip, 2019. [diakses: 9 Mei 2021].

Dawson, W. H. Roth, dan Drescher, “Slope Stability Analysis By Strength Reduction,” UC San Diego, 1999.

G.Lane, “Strength Reduction Stability,” Canada: Geo-Slope International Ltd, 1999.

R. F. Hirnawan, “Peran Faktor-Faktor Penentuan Zona Berpotensi Longsor dalam Mandala Geologi dan Lingkungan Fisiknya di Jawa Barat,” Majalah Ilmiah Universitas Padjajaran, 1994.

Hoek, Evert, dan John Bray, “Rock Slope Engineering,” The Institution Mining and Metallurgy. London, 1995.

R. D. Holtz dan W. D. Kovacs, “An Introduction to Geotechnical Engineering, Prentice Hall Civil Engineering and Engineering Mechanic Series,” 1981.

Instantel, “Minimate Plus Series III,” Canada, 2021.

Krahn dan Jhon, “The Limits of Limit Equilibrium Analysis,” Canada, 2007.

Nuryanto, “Analisis Stabilitas dan Desain Perkuatan Lereng Kawasan Sentul,” Jurnal Teknik Gunadarma, vol. 20, no. 2, 2021.

A. Pramulandani dan I. N. Hamdhan, “Analisis Stabilitas Lereng dengan Perkuatan Geocell Menggunakan Metode Elemen Hingga (PLAXIS 2D),” RekaRacana: Jurmal Teknik Sipil, vol. 6, no. 2, pp. 86-97, 2012.

R. Metriani, Y. M. Anaperta, dan T. G. Saldy, “Analisis Balik Kestabilan Lereng dengan Menggunakan Metode Bishop pada Front II Existing Tambang Quarry PT Semen Padang,” Jurnal Bina Tambang, vol. 4, no. 4, 2019. [online]. [diakses: 21 Maret 2021].

P. P. Hutayan dan T. Trides, “Analisis Pengaruh Air Tanah Terhadap Kestabilan Lereng Menggunakan Finite Element Method pada PT. Bharinto Ekatama, Kabupaten Kutai Barat, Kalimantan Timur,” Jurnal Teknologi Mineral FT UNMUL, vol. 2, no. 2, 2003.

M. Romana, J. B. Seron, dan E. Montalar, “SMR Geomechanics Classification for Slopes: Slope Mass Rating,” Comprehensive Rock Engineering, Editor: Hudson, J.A. Pergamon, 2003.

Sudjatmiko, “Peta Geologi Regional Lembar Cianjur. Pusat Pengembangan dan Penelitian Geologi,” Bandung, 1972.

Suratha Gde, “Kemantapan Lereng,” Direktorat Jenderal Pertambangan Umum Pusat Pengembangan Tenaga Pertambangan, Bandung, 1994.

T. Liong, Gouw, dan J. G. H. Dave, “Analisia Stabilitas Lereng Limit Equilibrium vs Finite Element Method,” Jakarta, 2012.

W. Bagus, dkk., “Pengaruh Tinggi Muka Air Tanah terhadap Kestabilan Jenjang pada Dinding Akhir Penambangan,” Jakarta: PERHAPI, 2006.

S. Wibowo, M. Rinaldi, A. M. Azzam, Z. Zakaria, dan I. Sophian, “Kajian Kestabilan Lereng Batuan Menggunakan Klasifikasi Masa Batuan, Metode Elemen Hingga dan Analisis Batuan Jatuh,” Padjajaran Geosience Jurnal. Vol. 2, no. 5, pp. 364-375, 2018.