Karakteristik Stabilitas Lereng Pada Highwall & Lowwall disertai Probabilitas Kelongsoran Pit AX – BX di Wilayah Kecamatan Binuang Kabupaten Tapin, Kalimantan Selatan

Mutiara Nabila Suardi, R. Febri Hirnawan, Indra Karna Wijaksana

Abstract


Abstract. At present, the research company in the Binuang District Area will make a new pit, the AX-BX Pit, so that safe and economical level design is needed by analyzing the slope stability. Factors affecting slope stability include; slope geometry, physical and mechanical properties of rocks, groundwater in a slope rock mass. To add confidence to the FK value, an additional analysis was performed using the probabilistic method. This problem is emphasized on factors that will affect slope stability as well as economics in mining. As for some identification of existing problems is ; there are differences in physical and mechanical properties of rock mass in the study area in each lithology as material properties and MAT slopes in the study area that affect rock strength. The purpose of this study is to determine the geometry and design recommendations for single and overall slopes for HW and LW in Section A and Section C Pit AX - BX based on the classification of FK and PK values in Ministerial Decree 1827/2018. The constituent rocks of the research location are composed of sedimentary rocks dominated by claystone. The strength of the rocks making up the study site is included in the classification of very weak rocks - weak rocks. The safe geometry for single slopes HW and LW in Section A : ϴ = 65˚ & H = 12 m for claystone and coal, ϴ = 60˚ for sandstone with H = 12 m. Section A slope design recommendations for HW slope : ϴoverall = 32˚, H = ± 189 m with FKdynamic values 1,187 & PK 19,90%. Section A for LW slope : ϴoverall = 37˚, H = ± 185 m with FKdynamic values 1,222 & PK 2,60%. Section C for HW slope : ϴoverall = 23˚, H = ± 234 m with FKdynamic values 1,164 & PK 13,20%. Section C for LW slope : ϴoverall = 24˚, H = ± 240 m with FKdynamic values 1,238 & PK 18,60%.

Keywords: Slope Stability, Probabilistic Method, FK (Safety Factor), PK (Failure Probability)

 

Abstrak. Saat ini pada perusahaan penelitian di Wilayah Kecamatan Binuang akan membuat pit baru yaitu Pit AX – BX, sehingga diperlukan pembuatan desain jenjang yang aman dan ekonomis dengan melakukan analisis stabilitas lereng. Faktor yang mempengaruhi stabilitas lereng, diantaranya yaitu ; geometri lereng, sifat fisik dan sifat mekanik batuan, air tanah didalam massa batuan lereng. Untuk menambah keyakinan terhadap nilai FK dilakukan analisis tambahan dengan metode probabilistik. Masalah yang ada ini dititikberatkan pada faktor-faktor yang akan mempengaruhi stabilitas lereng serta keekonomisan dalam penambangan. Adapun beberapa identifikasi masalah yang ada, yaitu ; adanya perbedaan sifat fisik dan mekanik massa batuan daerah penelitian pada setiap litologi sebagai material properties serta MAT lereng daerah penelitian yang mempengaruhi kekuatan batuan. Tujuan dari penelitian ini yaitu untuk mengetahui menentukan geometri dan rekomendasi desain lereng single dan overall untuk HW dan LW pada Section A dan Section C Pit AX – BX berdasarkan klasifikasi nilai FK dan PK pada Kepmen 1827/2018. Batuan penyusun lokasi penelitian tersusun dari batuan sedimen yang didominasi oleh claystone. Kekuatan batuan penyusun lokasi penelitian termasuk ke dalam klasifikasi batuan sangat lemah sekali – batuan lemah. Geometri yang aman untuk lereng tunggal HW dan LW pada Section A yaitu ϴ = 65˚ & H = 12 m untuk claystone dan coal, ϴ = 60˚ untuk sandstone dengan H = 12 m. Rekomendasi desain lereng Section A lereng HW : ϴoverall= 32˚, H = ± 189 m dengan nilai FKdinamis 1,187 & PK 19,90%. Section A lereng LW : ϴoverall= 37˚, H = ± 185 m dengan nilai FKdinamis 1,222 & PK 2,60%. Section C lereng HW : ϴoverall= 23˚, H = ± 234 m dengan nilai FKdinamis 1,164 & PK 13,20%. Section C lereng LW : ϴoverall= 24˚, H = ± 240 meter dengan nilai FKdinamis 1,238 & PK 18,60%.

Kata Kunci: Stabilitas Lereng, Metode Probabilistik, FK (Faktor Keamanan), PK (Probabilitas Kelongsoran)


Keywords


Stabilitas Lereng, Metode Probabilistik, FK (Faktor Keamanan), PK (Probabilitas Kelongsoran)

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