Pore Changes in Purple Mudstone Based on the Analysis of Dry-Wet Cycles Using Nuclear Magnetic Resonance

Dang, Chen; Sui, Zhili; Yang, Xiuyuan; Ge, Zhenlong

doi:10.1155/2022/5578401

Cited by 4 publications

(2 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Some scholars have also studied the effect of cyclic dry-wet conditions on sandstone by visualizing and quantifying the distribution of microstructure in rock through 3D reconstruction and mixed image segmentation of CT images [19,20] and surface topography scanning tests [21]. Dang et al [22] analyzed the relationship between pore size changes and porosity through NMR tests and studied the evolution of microscopic pore structure of rocks and soils after different dry-wet cycles.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Pore Structure Evolution of Unloaded Rock Mass during Excavation of Reservoir Slope under Dry–Wet Cycle

Chen,

Gong

et al. 2024

Applied Sciences

View full text Add to dashboard Cite

There is a long sequence of periodic characteristics of reservoir water storage and discharge in large hydropower stations. The unloaded rock mass formed by blasting and excavation in the reservoir slope of the reservoir fluctuation zone is not only subjected to the penetration erosion caused by the change of the water level of the reservoir slope, but also the dry–wet cycle caused by the reservoir water storage and discharge. There is an obvious process of crack derivation and pore structure expansion, and the subsequent strength degradation breeds reservoir slope risks, which is one of the important factors restricting the operation safety of power stations. To study the pore structure evolution law of unloaded rock mass in reservoir slope excavation of reservoir fluctuation zones, the dry–wet cycle test simulating the periodic storage and discharge environment was carried out with samples of equal unloading amount obtained by indoor triaxial unloading test. The variation law of mesoscopic parameters such as wave velocity, mass, and nuclear magnetic resonance spectrum under dry–wet cycle was compared and analyzed, and the physical and mechanical mechanism of the pore structure evolution of the unloaded specimen under dry–wet cycles was explored. The results show that: (1) With the increase of dry–wet cycles, the evolution of wave velocity and dry mass of unloaded samples has obvious stage characteristics, which generally presents a rapid change in the early stage, moderate in the middle stage, and gradually stable in the late stage; (2) nuclear magnetic resonance (NMR) shows that the number of macropore structures in unloaded samples increases gradually with the dry–wet cycles; (3) the smaller the initial confining pressure, the larger the first peak area and the peak value of unloaded samples, and the spectral area corresponding to each peak under low confining pressure is significantly larger than that under medium and high confining pressure; (4) the unloading amount affects the overall proportion of macropores in the sample, which determines the deterioration process and evolution law of the mesostructure of the sample under dry–wet cycles.

show abstract

Section: Introductionmentioning

confidence: 99%

Experimental Study on Pore Structure Evolution of Unloaded Rock Mass during Excavation of Reservoir Slope under Dry–Wet Cycle

Chen,

Gong

et al. 2024

Applied Sciences

View full text Add to dashboard Cite

show abstract

“…Many studies have explained that mesodamage is accompanied by pore closure and pore expansion in rock. 26,27 In general, the T2 curve 28 and pore volume ratio 29 are used to study mesodamage, and the effect of the quantitative variation description is not sufficiently precise. Therefore, there is a lack of mesoscale damage indexes to describe the quantitative variations in rock.…”

Section: Introductionmentioning

confidence: 99%

Dynamic response and damage evolution of red sandstone with confining pressure under cyclic impact loading

Wang

Guo

et al. 2022

Fatigue Fract Eng Mat Struct

View full text Add to dashboard Cite

Abundant mesoscale damage occurs prior to rock destruction, and the change in porosity can reflect the dynamic mechanical characteristics of the rock. In this study, red sandstone specimens were dynamically loaded by a split Hopkinson pressure bar (SHPB) with confining pressure. The change in porosity was reflected by the new index of porosity variation rate (Rv), and the relationships between the cyclic impact and the dynamic characteristics and porosity variation were analyzed. The average filtering algorithm was emphasized to remove the noise of grayscale NMR images. It was concluded that the number of impacts before crushing gradually decreases with increasing air pressure for the overall trend, there is no obvious rebound, and the energy dissipation increases before the crushing of the specimens. There is an abrupt difference in the dynamic characteristics between the third impact and the fourth impact. The pore space changes from medium and large pores to micropores with impact loading. The peak of the microporous porosity difference curve shifts to smaller micropores. The new index can describe pore closure and expansion. The image processing method used in this work obtained accurate statistical information that confirms the presence of a large number of microcracks before crushing.

show abstract

Study on the effect of high-temperature dry–wet cycles on argillaceous sandstone

Wang

Sun

Xue

et al. 2023

Bull Eng Geol Environ

View full text Add to dashboard Cite

Pore Changes in Purple Mudstone Based on the Analysis of Dry-Wet Cycles Using Nuclear Magnetic Resonance

Cited by 4 publications

References 39 publications

Experimental Study on Pore Structure Evolution of Unloaded Rock Mass during Excavation of Reservoir Slope under Dry–Wet Cycle

Experimental Study on Pore Structure Evolution of Unloaded Rock Mass during Excavation of Reservoir Slope under Dry–Wet Cycle

Dynamic response and damage evolution of red sandstone with confining pressure under cyclic impact loading

Study on the effect of high-temperature dry–wet cycles on argillaceous sandstone

Contact Info

Product

Resources

About