STABILITY ANALYSIS OF TRANS-SUMATRA TOLL ROAD TUNNEL USING ROCK MASS CLASIFICATION IN PAYAKUMBUH – PANGKALAN SECTION, WEST SUMATRA

• Main Author: Sebastian Santoso, Fernaldy
• Format: Final Project
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/41596
• Institution: Institut Teknologi Bandung

Trans-Sumatra national highways toll road tunnel project in Payakumbuh-Pangkalan section is planned to reduce time cost and distance covered by the vehicles that are passing by, prior to previous existing road that has numerous winding road with steep side slopes. Research area is located on Air Putih and Buluh Kasok Village, Harau Sub-Disctrict, Lima Puluh Kota Regency, West Sumatra Province at coordinates of 0o 07’ 26.2632’’ S, 100o 41’ 32.0293’’ E to 0o 05’ 30.5628’’ U, 100o 45’ 16.9632’’ E. This research was conducted in order to determine the ratings from the rock mass using Rock Mass Rating (RMR) and Q-System classifications and also to evaluate tunnel stability using RMR and Q-System classifications in a toll road tunnel project. Empirical methods of RMR and Q-System were being used in determining ratings of rock mass in six different locations, which were PA, PB, PC, PD, PE and PF. Numerical analyses of tunnel stability using finite element method were conducted afterward concerning in Strength Factor (SF) and total displacement parameters, followed by evaluation of tunnel stability. Based on field observation, lithology of PA, PB and PE are composed by quartzite and lithology of PC, PD and PF are composed of slate. RMR classification show the rock mass class of III (fair rock) in location PA, PB and PE and class of IV (poor rock) in location PC, PD and PF. Q-System classification show the rock mass class of fair rock in location PA and PB and class of poor rock in location PC, PD, PE and PF. According to RMR classification results, rock support design recommendation of shotcrete, wire mesh, rock bolt and steel sets were proposed while based on Q-System classification result, recommendation of fiber reinforced shotcrete and rock bolt were proposed. Numerical analyses performed using the rock support recommendation design from RMR classification resulted in a SF value ranged from 1.03 – 4.97 and total displacement value ranged from 0 – 29 mm while recommendation design based on Q-System classification resulted in a SF value ranged from 1.03 – 5.17 and total displacement value ranged from 0 – 23 mm. Evaluation conducted from previous analyses showed that Q-System based rock support performed better in fair rock mass and or poor rock mass with relatively low overburden while RMR based rock support was more suitable for poor rock mass with relatively high overburden.