Perhitungan Rmr Dab Q, Soal.docx

Question 1: 

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In a 10m wide tunnel for power station, the ground conditions have been characterized as follows: A granite with uniaxial compressive strength, σc = 125MPa is penetrated by 2 joint sets, both with favourable orientation of the main joint set. In addition, some random joints occur. Average degree of jointing is: RQD = 85; block volume, joint spacing, S = 0.2 – 0.4m. The fresh, continuous joints of the main set are rough & planar, tight and mostly longer than 3m. It is “damp” water condition, and approximately 100m rock overburden, i.e. medium stress level. Estimate value of Q , RMR

Question 2 

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In a 4.2 x 4.8 tunnel for permanent mine opening, the ground conditions have been characterized as follows: A breccia smectite with uniaxial compressive strength, σc = 40 MPa is penetrated by 3 joint sets. With very unfavourable orientation of the main joint set. Average degree of jointing is: RQD = 55; joint spacing, S = 0.2 – 0.4m, The slightly weathered, continuous joints of the main set are smooth & undulating, tight (0.1-1m) with compated clay filling and mostly longer than 3m. It is “wet to damp ” water condition, and approximately 88m rock overburden, i.e. medium stress level. Estimate value of RMR and Q,

JAWAB: Tabel Rock Mass Rating System (After Bieniawski, 1989).

Tabel Classification of individual parameters used in the Tunnelling Quality Index Q (After Barton et al, 1974).