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Geomechanics and Engineering Volume 38, Number 1, July10 2024 , pages 045-56 DOI: https://doi.org/10.12989/gae.2024.38.1.045 |
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Mechanical damage evolution and a statistical damage constitutive model for water-weak sandstone and mudstone |
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Lu yuan Wu, Fei Ding, Jian hui Li and Wei Qiao
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| Abstract | ||
| The weakening effect of water on rocks is one of the main factors inducing deformation and failure in rock engineering. To clarify this weakening effect, immersion tests and post-immersion triaxial compression tests were conducted on sandstone and mudstone. The results showed that the strength of water-immersed sandstone decreases with increasing immersion time, exhibiting an exponential relationship. Similarly, the strength of water-immersed mudstone decreases with increasing environmental humidity, also following an exponential relationship. Subsequently, a statistical damage model for water-weakened rocks was proposed, changes in elastic modulus to describe the weakening effect of water. The model effectively simulated the stress-strain relationships of water-affected sandstone and mudstone under compression. The R2 values between the theoretical and experimental peak values ranged from 0.962 to 0.996, and the MAPE values fell between 3.589% and 9.166%, demonstrating the model's effectiveness and reliability. The damage process of water-saturated rocks corresponds to five stages: compaction stage - no damage, elastic stage - minor damage, crack development stage - rapid damage increase, post-peak residual stage - continuous damage increase, and sliding stage - damage completion. This study provides a foundational reference for researching the fracture characteristics of overlying strata during coal mining under complex hydrogeological conditions. | ||
| Key Words | ||
| ambient humidity; immersion time; rock constitutive model; rock damage; water-weak | ||
| Address | ||
| Lu yuan Wu, Fei Ding and Jian hui Li: School of Civil Engineering and Architecture, Henan University, Jin ming Street, Kaifeng, 475001, Henan, China Wei Qiao: School of Resources and Earth Sciences, China University of Mining and Technology, Xuzhou, 221116, Jiangsu, China | ||