Evolution of the Unfrozen Water Content for Partially-Saturated Sandstones and the Critical Degree of Saturation

Weng, Lei; Wu, Zhijun; Chu, Zhaofei; Lu, Haifeng; Xu, Xiangyu; Liu, Quansheng

doi:10.1007/s00603-022-03081-6

Cited by 19 publications

(2 citation statements)

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“…Moreover, the NMR technology can be employed to interpret the pore and fracture structures of rocks. [46][47][48][49] First, the investigated sandstone specimens are vacuumed for 6 h in the vacuum saturator under the pressure of À0.1 MPa. Then the water saturation condition with the hydrostatic pressure of 10 MPa is kept for 24 h to obtain the saturated sandstone specimens.…”

Section: Nmr (Nuclear Magnetic Resonance) Testmentioning

confidence: 99%

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Assessment on anisotropy degree and fracture modes for weakly anisotropic sandstone using the acoustic emission technique

Zheng

Wang

Zhao

et al. 2023

Fatigue Fract Eng Mat Struct

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Comprehensive understanding of anisotropy characteristics and fracture modes for weakly anisotropic rocks is required for engineering safety and energy exploitation. To investigate the fracture mechanisms, the uniaxial compression testing with AE (acoustic emission) technique is implemented on the weakly anisotropic sandstone because of its capability to provide the essential and frequently-used mechanical parameters. This research first adopts the longitudinal wave velocity and T 2 spectrum to validate the weak anisotropy of the bedded sandstone. The results experimentally indicate that both uniaxial compressive strength and Young's modulus have a negligible dependence on different bedding orientation angles, but both permeability and macroscopic failure patterns are considerably controlled by the bedding direction. The conventional AE index analysis indicates that the tension-dependent failure occurs in the bedded sandstone under the uniaxial compression. Interestingly, the developed k-means clustering method is consistent with both the latest crack classification concept and macroscopic failure patterns. K E Y W O R D S acoustic emission, fracture modes, k-means clustering, macroscopic failure patterns, weakly anisotropic sandstone Highlights • The weak anisotropy of the sandstone specimens is validated by the wave velocity and T 2 spectrum. • The anisotropy properties and fracture mechanisms are analyzed using the acoustic emission (AE) monitoring technique. • The k-means clustering method is developed by this work to compare the conventional AE parameter (RA and AF) analysis.

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Section: Nmr (Nuclear Magnetic Resonance) Testmentioning

confidence: 99%

“…Moreover, the NMR technology can be employed to interpret the pore and fracture structures of rocks 46–49 . First, the investigated sandstone specimens are vacuumed for 6 h in the vacuum saturator under the pressure of −0.1 MPa.…”

Section: Specimen Preparation and Experiments Proceduresmentioning

confidence: 99%