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Acta Armamentarii ›› 2023, Vol. 44 ›› Issue (12): 3805-3814.doi: 10.12382/bgxb.2023.0690

Special Issue: 爆炸冲击与先进防护

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Dynamic Mechanical Properties and Damage Constitutive Model of Copper-bearing Garnet-biotite Schist

ZHAO Zehu, LI Xianglong*(), HU Qiwen**(), WANG Jianguo   

  1. School of Land and Resources Engineering, Kunming University of Science and Technology, Kunming 650093, Yunnan, China
  • Received:2023-07-25 Online:2023-12-30
  • Contact: LI Xianglong, HU Qiwen

Abstract:

The dynamic mechanical properties and damage law of deep ore rock under different loading conditions are explored by taking the copper-bearing garnet biotite schist in deep mining as an object of study. A combined dynamic and static impact test is performed under the conditions of six kinds of axial pressure σap (0MPa, 6MPa, 12MPa, 18MPa, 24MPa, 30MPa), six kinds of confining pressure σp (0MPa, 4MPa, 8MPa, 12MPa, 16MPa, 20MPa) and six kinds of impact velocity v (18.68m/s, 20.93m/s, 23.54m/s, 26.63m/s, 29.26m/s, 31.95m/s), and the factors of impact velocity, axial pressure, confining pressure and strain rate are considered. Based on the statistical damage theory and Drucker-Prager failure criterion, a dynamic damage constitutive model of copper-bearing garnet-biotite schist under combined static and dynamic loading is established. The results show that there is almost no compaction stage in the stress-strain curve of ore rock specimen. When the stress increases to 65%-80% of peak stress, the stress-strain curve of this stage shows a step phenomenon. The dynamic failure mode of deep surrounding rock is significantly affected by the stress state and impact velocity of ore rock at different buried depths.When σp=12MPa and v=31.95m/s, the dynamic compressive strength increases first and then decreases with the increase of axial compression σap, while the peak strain decreases linearly. When σp=12MPa and σap=24MPa, the dynamic compressive strength increases linearly with the increase of strain rate, while the peak strain increases as quadratic polynomial with the increase of strain rate. The theoretical curve of the model is in good agreement with the experimental curve, which verifies the reliability of the dynamic constitutive model, and can provide some reference for the research and engineering application of the dynamic constitutive model of deep buried rock mass.

Key words: copper-bearing garnet-biotite schist, static-dynamic coupling loading, failure mode, Drucker-Prager failure criterion, dynamic damage constitutive model

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