Effect of Coal Pick Excavation on Tunnel Stability Constituent Rock Parameters

Abstract

Underground mining is a mining method in which all mining activities or activities are carried out below the surface of the earth. The purpose of this study is to analyze the quality of rock mass in the tunnel, in terms of the physical, mechanical, and dynamic properties of the rock, as well as observe the influence of coal pick hammer vibration on the stability of the tunnel. and determine supporting recommendations in tunnel 9. The Pundit Test for coal sample with R2 = 0.9023 is obtained. The correlation P-wave with index strength got R2 = 0.8977. For correlation between P-wave and Schmidt Hammer Rebound Number got R2 = 0.9699. Tunnel support recommendation for the AICJ-09 Tunnel with “Q” value of 1.8 and 1.6, it belongs to the poor rock class. Microtremor measurement got the highest vibration value occurred at station 11, where 2 high vibration values ​​were found, namely 0.159 m/s2 and 0.261 m/s2. This happens because the vibration of the coal pick increases because it is influenced by coal transportation activities and there are also additional vibrations originating from the compressor machine working around station 11. Vibration causes a decrease in the value of the tunnel safety factor. The analysis's findings showed that the safety factor's value had decreased. However, the safety factor is still considered safe against tunnels. Where the standard tunnel safety factor of 1 is said to be a stable tunnel.