Analisis Kualitas dan Perkuatan Terowongan Eksplorasi Uranium Eko Remaja Kalan, Kalimantan Barat menggunakan Metode RMR (Rock Mass Rating)

Yuni Faizah, Wira Cakrabuana, Dhatu Kamajati, Putri Rahmawati

DOI: http://dx.doi.org/10.55981/eksplorium.2020.5859

Abstract


ABSTRAK Terowongan Eksplorasi Uranium Eko Remaja Kalan (TEURK) di Kalimantan Barat yang dibangun pada tahun 1980 merupakan salah satu sarana penelitian cebakan uranium di Indonesia. Terowongan ini menembus Bukit Eko Remaja sepanjang 618 m, mulai dari pintu Remaja hingga TRK-7. Mineralisasi uranium di lokasi ini dikontrol oleh urat-urat tak beraturan (stockwork) yang sangat rapat pada batuan metalanau dan metapelit. Tingginya kerapatan struktur geologi tersebut membentuk beberapa zona lemah di dalam terowongan. Zona lemah tersebut berpotensi menyebabkan terjadinya longsor batu dan tanah. Penyangga sementara terbuat dari tiang-tiang kayu dipasang di zona tersebut untuk perkuatan terowongan. Saat ini tiang kayu tersebut tidak lagi mampu menyangga terowongan sehingga sering terjadi longsor batu dan tanah di dalam terowongan. Penelitian ini bertujuan untuk mengetahui kualitas massa batuan aktual dan menentukan jenis perkuatan yang sesuai agar terowongan tetap aman. Survei palu Schmidt dan scanline pada zona tak berpenyangga (kedalaman 50–297 m dan 355–538 m) dilakukan untuk mengambil data parameter klasifikasi Rock Mass Rating (RMR). Hasil pengukuran menunjukkan bahwa massa batuan TEURK di kedalaman tersebut memiliki nilai RMR 52-71 (sedang–baik). Perkuatan yang direkomendasikan adalah pemasangan baut batu dan beton semprot konvensional.

ABSTRACT Tunnel for Exploration of Uranium Eko Remaja Kalan (TEURK) in West Kalimantan, built-in 1980, is one of the uranium deposit research facilities in Indonesia. The tunnel penetrated Eko Remaja Hill along 618 m, from Remaja to TRK-7 access. Uranium mineralization in this area controlled by dense stockwork veins on metasilt and metasandstone rocks. The high-dense geological structures create some weak zones in the tunnel. These zones are potentially causing rocks and soil slides. Temporary supports made of wood-piles were installed in these zones to support the tunnel. Currently, these piles are not capable at the tunnel, so that rocks and soil slides occurred inside the tunnel. The research aimed to determine the quality of actual rock mass and determine the appropriate type of reinforcement to keep the tunnel safe. Schmidt hammer and scanline surveys on the unsupported zone (50–297 m and 355–538 m depth) carried out to collect the classification parameter data of Rock Mass Rating (RMR). The measurement result shows that the rock mass of TEURK on the depth has an RMR value of 52–71 (fair-good). Reinforcement recommendations for the tunnel are rock bolts and conventional shotcretes installation.


Keywords


terowongan; palu Schmidt; scanline, RMR; perkuatan

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