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Nuclear magnetic resonance analysis of the failure and damage model of rock masses during freeze‒thaw cycles
Abstract Multiple freeze–thaw cycle tests were conducted on sandstone samples. The sandstone samples were examined using X-ray diffraction (XRD) and nuclear magnetic resonance (NMR). The mineral content, porosity distribution, $ T_{2} $ (transverse relaxation time) spectral distribution, spectral area, and nuclear magnetic resonance imaging (MRI) data for sandstone samples were obtained, and the distribution and variation of the sample pores were analyzed. Uniaxial compression tests were performed on samples that had undergone 0, 20, 40, and 80 freeze‒thaw cycles, and the effects of freeze‒thaw cycles on the mass, compressive strength, and elastic modulus of the sample were analyzed. The damage evolution and strength degradation characteristics of sandstone after freeze‒thaw cycles were studied. As the number of freeze‒thaw cycles increases, mineral particle flaking and cracking appear on the rock surface, the uniaxial compressive strength and elastic modulus of rock samples decrease, and the typical stress–strain curve compaction stage corresponding to the deformation increases. According to the NMR $ T_{2} $ distribution, the pore size of rock samples increases after 80 freeze‒thaw cycles, especially that of medium-sized and small-sized pores. Meanwhile, the internal damage to the rock mass is a gradual process of cumulative fatigue damage caused by freezing and thawing, and the microscopic damage evolution law during freeze‒thaw cycles was revealed using MRI. Based on plasticity theory and damage fracture mechanics theory, the sandstone damage propagation criterion under freeze‒thaw-loading action was deduced, and a sandstone freeze‒thaw damage degradation model was established.
Nuclear magnetic resonance analysis of the failure and damage model of rock masses during freeze‒thaw cycles
Abstract Multiple freeze–thaw cycle tests were conducted on sandstone samples. The sandstone samples were examined using X-ray diffraction (XRD) and nuclear magnetic resonance (NMR). The mineral content, porosity distribution, $ T_{2} $ (transverse relaxation time) spectral distribution, spectral area, and nuclear magnetic resonance imaging (MRI) data for sandstone samples were obtained, and the distribution and variation of the sample pores were analyzed. Uniaxial compression tests were performed on samples that had undergone 0, 20, 40, and 80 freeze‒thaw cycles, and the effects of freeze‒thaw cycles on the mass, compressive strength, and elastic modulus of the sample were analyzed. The damage evolution and strength degradation characteristics of sandstone after freeze‒thaw cycles were studied. As the number of freeze‒thaw cycles increases, mineral particle flaking and cracking appear on the rock surface, the uniaxial compressive strength and elastic modulus of rock samples decrease, and the typical stress–strain curve compaction stage corresponding to the deformation increases. According to the NMR $ T_{2} $ distribution, the pore size of rock samples increases after 80 freeze‒thaw cycles, especially that of medium-sized and small-sized pores. Meanwhile, the internal damage to the rock mass is a gradual process of cumulative fatigue damage caused by freezing and thawing, and the microscopic damage evolution law during freeze‒thaw cycles was revealed using MRI. Based on plasticity theory and damage fracture mechanics theory, the sandstone damage propagation criterion under freeze‒thaw-loading action was deduced, and a sandstone freeze‒thaw damage degradation model was established.
Nuclear magnetic resonance analysis of the failure and damage model of rock masses during freeze‒thaw cycles
Liu, Taoying (author) / Cui, Mengyuan (author) / Zhang, Chaoyang (author) / Zhou, Keping (author) / Shi, Wenchao (author) / Cao, Ping (author)
2022
Article (Journal)
Electronic Resource
English
BKL:
56.00$jBauwesen: Allgemeines
/
38.58
Geomechanik
/
38.58$jGeomechanik
/
56.20
Ingenieurgeologie, Bodenmechanik
/
56.00
Bauwesen: Allgemeines
/
56.20$jIngenieurgeologie$jBodenmechanik
RVK:
ELIB18
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