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TUGAS PRAKTIKUM MEKANIKA BATUAN ACARA 6 (rOCK QUALITY DESIGNATION)

TUGAS PRAKTIKUM MEKANIKA BATUAN ACARA 6 (rOCK QUALITY DESIGNATION)26 Mei 2014

1. Grafik Rock Mass Rating, Penentuan Span dan Stand Up Time

Keterangan : Sumbu X : Menunjukkan Stand Up Time (Jam), Skala logaritmik Sumbu Y : Jarak Span dengan keadaan atap tanpa didukung (meter), skala normal

Parameter yang Didapat dari Grafik Nilai RMR: Nilai Stand Up Time (Jam) Jarak Span (meter) Waktu Ketahanan Batuan Sebelum Runtuh Tanpa Penyanggaan Perlu / Tidaknya Penyanggaan

TABEL ROCK MASS RATING SYSTEM (Bienawski, 1989)

TABEL KLASIFIKASI NILAI RMR TERHADAP PENGGARUAN DAN JENIS PENYANGGAAN

2. Soal

Diketahui :- Is = 7 MPa- Spasi discontinue = 500 mm- Roughness = smooth- Filling = Hard Filling < 5 mm- Pelapukan = Moderately- Aparture= 0,9 mm-- Persistensi = 3 m- Kondisi Discontinue= Slightly rough surfacesseparation - Koreksi = Drive With Dip 30o< 1 mm Slightly weathered walls- Nilai RQD = Perconto A : 41,8 % Perconto B : 85,25 % Perconto C : 72,75 %Pembahasan - Is = 7 MPa (Poin : 12)- Spasi discontinue = 500 mm (Poin : 10 )- Roughness = smooth (Poin : 1 )- Filling = Hard Filling < 5 mm (Poin : 2 )- Pelapukan = Moderately (Poin : 3)- Aparture= 0,9 mm (Poin : 4 )-- Persistensi = 3 m (Poin : 4 )- Kondisi Discontinue= (Poin : 25 )- Nilai RMR = Perconto A : 41,8 % (Poin : 8 + 51 = 59) CN :3 (Fair Rock), Butuh Penyanggaan Span 17 m, Stand Up Time 8000 jam Perconto B : 85,25 % (Poin : 13 + 51 = 64) CN :2 (Good Rock), Butuh Penyanggaan Span 18 m, Stand Up Time 11000 jam Perconto C : 72,75 % (Poin : 17 + 51 = 68) CN :2 (Good Rock), Butuh Penyanggaan Span 19 m, Stand Up Time 14000 jam Koreksi = Drive With Dip 30o(Favourable) -2

3. Mendapatkan Nilai RQD tanpa coreApabila tidak ada data lubang bor yang tersedia, rentang nilai RQD dapat diperkirakan dengan menggunakan hubungan diperkenalkan oleh Hudson - Priest ('79) dan ISRM ('78), dengan mempertimbangkan rata-rata rentang diskontinuitas (x) dan Jv (jumlah diskontinuitas per meter kubik batu) seperti digambarkan pada rumus sebagai berikut :

Dimana: X : Rata rata rentang diskontinuitas Jv : Jumlah diskontinuitas per meter kubik batu : 1/x4. Diagram Alir Klasifikasi Batuan

Referensi :1.Anonim. Experiences with the Rock Mass Rating RMR (System) or the Geomechanical Classification System for rocks. http://www.geoinvestigate.co.uk/rockmass-classification-revisited-experiences-with-the-rock-mass-rating-rmr-system-or-the-geomechanical-classification-system-for-rocks. Tanggal Akses 27 Mei 2014 pukul 17:32 WIB.2.Anonim. Rock Mass System and its Aplication to Engineering Technicality. http://www.kocea.or.kr/jsp/edu/eduTm/eduView011.jsp?seq=40&tiseq=130&ord=10&iPage=21&sk=&sg=&gbn=&title=%BE%CF%B9%DD%BB%E7%B8%E9%C0%C7%20%BE%C8%C1%A4%B4%EB%C3%A5. Tanggal Akses 27 Mei 2014 pukul 17:36 WIB.3. Bieniawski, Z.T. 1989. Engineering rock mass classifications.New York: Wiley.4. Deere, D.U. and Deere, D.W. 1988. The rock quality designation (RQD) index in practice. In Rock classification systems for engineering purposes,(ed. L.Kirkaldie), ASTM Special Publication 984, 91-101. Philadelphia: Am. Soc. Test. Mat.3. Yannakoyorgos, Andreas. Tunnel Support Design Using Empirical Method. http://andreasyannakoyorgos.blogspot.com/2011/11/tunnel-support-design-using-empirical.html. Tanggal Akses 27 Mei 2014 pukul 17:24 WIB.

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