ANALYSIS OF REINFORCEMENT SYSTEM (ROCK BOLT AND SHOTCRETE) EFFECT ON THE PILLARS STRENGTH IN UNDERGROUND MINING USING PHYSICAL MODELS TESTING IN LABORATORY

• Main Author: Ode Dzakir, La
• Format: Theses
• Language: Indonesia
• Subjects: Teknik (Rekayasa, enjinering dan kegiatan berkaitan)
• Online Access: https://digilib.itb.ac.id/gdl/view/32654
• Institution: Institut Teknologi Bandung

Pillars are natural supports which hold the material load on top. As a natural support, pillars require a special reinforcement system so they do not experience failure during underground mining activities. In this study, physical model of the pillar was made of a mixture of sand, cement and water, with strengths resembling coal strength in Indonesia. Then the pillars are divided into four types, that are pillars without reinforcement, pillars with reinforcement of rock bolt, pillars with reinforcement of shotcrete and pillars with combined reinforcement of rock bolt and shotcrete. Furthermore, the pillars are tested with compressive strength machines to determine the effect of the reinforcement system on the pillars. The results of this study indicate that the reinforcement system on high strength pillars causes a strength increase of 14.93% on pillar with rock bolt reinforcement, 21.45% on pillar with shotcrete reinforcement and 34.67% on pillar with combination of rock bolt and shotcrete reinforcement. On medium strength pillars, reinforcement installation shows a strength increase of 16.27% on pillar with reinforced rock bolt, 19.83% on pillar with reinforced shotcrete and 44.40% on pillar with combination of rock bolt and shotcrete reinforcement. Likewise, on low strength pillars, reinforcement installation causes a strength increase of 13.13% on pillar with reinforced rock bolt, 36.21% on pillar with reinforced shotcrete and 53.85% on pillar with combination of rock bolt and shotcrete reinforcement. Laboratory test and numerical modeling results show that the increase in strength occurs because the horizontal displacement on the pillar wall is held by shotcrete and retaining plate on rock bolt so that the pillar appears to be confining pressure which causes the horizontal displacement on the surface of pillar wall to be smaller than the horizontal displacement on pillar without reinforcement.