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Damage mechanism of sandstone subjected to different prestress levels: insight from the mesoscopic perspective
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  • Yaxin Zhang,
  • Lixu Deng,
  • Guodong Zhang,
  • Jianfei Yang,
  • Xijun Li
Yaxin Zhang
China Three Gorges University

Corresponding Author:[email protected]

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Lixu Deng
China Three Gorges University
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Guodong Zhang
China Three Gorges University
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Jianfei Yang
China Three Gorges University
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Xijun Li
China Three Gorges University
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Abstract

This study aimed to elucidate the damage mechanism of prestressed sandstone under uniaxial compression through the distribution characteristics of meso-structures. Four prestress levels, i.e., 0MPa, 15MPa, 30MPa, and 40MPa were selected. Nuclear Magnetic Resonance and Scanning Electron Microscope techniques were employed to observe the distribution characteristics of meso-structure within rocks and to further its damage mechanism. The results show that, compare with untreated specimens (0MPa), damaged specimens by 15MPa show a more porous meso-structure due to pores/cracks propagation which occurs between skeleton minerals and filler materials. Furthermore, specimens treated by 30MPa and 40MPa show low failure strength because micro-pores/cracks initiation inside skeleton minerals causes high deterioration. By meso-mechanics analysis, particle rotation leads to pores/cracks propagation and slightly modifies the meso-structure under low-prestress conditions. With the increase of the prestress, the transgranular cracks initiation and propagation will transform the skeleton structure of rocks, leading to significant rock deterioration.