TN1025 : Numerical Modeling of Rockburst in Deep Hard Rock Mines
Thesis > Central Library of Shahrood University > Mining, Petroleum & Geophysics Engineering > MSc > 2021
Authors:
Mohammad Omidi [Author], Farhang Sereshki[Supervisor], mehdi noroozi[Supervisor], Hossein janjani avarzaman [Advisor]
Abstarct: One of the main threads which might lead to irreversible damages to mine and its labour is rockburst as it gets deeper into the ground. To prevent its consequences, predicting this phenomenon has been turned into a vital issue for miners as they excavating deeper. Using finite element software has been greatly developed to overcome this obstacle. By implementing Abaqus software, tried to simulate the underground basalt mine which had gone under the seismic test. Mentioned mine exploded spontaneously in the tunnel’s face, as well as at the intersection of the main tunnel and cross-cut. Given that this region is affected by seismicity, the Rayleigh coefficients of the environment, which are the damping coefficients of the wave, must first be determined. This has been done with an innovative method in this research. Also, using reverse analysis, the source wave that was received by Geophone at a distance of 340 and 630 meters has been identified. The present study has predicted the areas with the highest concentration of stress (σ_33) of the mine in face and cross-cut1 to be 47/4 and 29 MPa, respectively; Because the model can identify these areas before the earthquake, by identifying these areas. The results of this study also indicate that the earthquakes generated by the surrounding faults increase the stress by 0.2 and 3.2 MPa and have an effect on the occurrence of this phenomenon as a primer. τ_12 and σ_(22 )had their maximum values (1.2 and 10 MPa) in the tunnel, respectively, at the face and cross-cut1, which is a reason for the susceptibility of the upper corner of the face and the intersection of cross-cut1 for rockburst. At the end of this study, sensitivity analysis was performed and solutions such as shrinking the tunnel, digging the overhead tunnel and step drilling to reduce the risk of rockburst were performed. 33 and 50% reduction of tunnel dimensions reduced the stress by 24.9% and 29.4% of face and 29 and 34.4% of cross-cut. Step drilling reduced 21.5% and 17% in face and cross-cut1. Also, the creation of a tunnel with a diameter of 3 meters reduced the concentration of stress by 14.7 and 31% in the face and cross-cut1 and the creation of a horseshoe tunnel reduced the concentration of stress in the face and cross-cut1, 8.6 and 10%.
Keywords:
#rockburst #Numerical simulation #Seismic #Abaqus Keeping place: Central Library of Shahrood University
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