Pore structure variation characteristics of a Chinese local mudstone before and after the first cycle of wetting and drying

Abstract

As a typical sedimentary soft rock, mudstone has the characteristics of being easily softened and disintegrated under the effect of wetting and drying (WD). The first cycle of WD plays an important role in the entire WD cycles. X-ray micro-computed tomography (micro-CT) was used as a non-destructive tool to quantitatively analyze microstructural changes of the mudstone due to the first cycle of WD. The test results show that WD leads to an increase of pore volume and pore connectivity in the mudstone. The porosity and fractal dimension of each slice of mudstone not only increase in value, but also in fluctuation amplitude. The pattern of variation in the frequency distribution of the equivalent radii of connected, isolated pores and pore throats in mudstone under WD effect satisfies the Gaussian distribution. Under the effect of WD, pores and pore throats with relatively small sizes increase the most. The sphericity of the pores in mudstones is positively correlated with the pore radius. The WD effect transforms the originally angular and flat pores into round and regular pores. This paper can provide a reference for the study of the deterioration and catastrophic mechanisms of mudstone under wetting and drying cycles.

References

[1] ZhouC-y, DengY-m, TanX-s, et al.. Experimental research on the softening of mechanical properties of saturated soft rocks and application [J]. Chinese Journal of Rock Mechanics and Engineering, 2005, 24(1): 33-38(in Chinese)

[2] KongL-w, ZengZ-x, BaiW, et al.. Engineering geological properties of weathered swelling mudstones and their effects on the landslides occurrence in the Yanji section of the Jilin-Hunchun high-speed railway [J]. Bulletin of Engineering Geology and the Environment, 2018, 77(4): 1491-1503

[3] ZhangJ, MaG-d, MingR-p, et al.. Numerical study on seepage flow in pervious concrete based on 3D CT imaging [J]. Construction and Building Materials, 2018, 161: 468-478

[4] WuQ, XuY-j, TangH-m, et al.. Investigation on the shear properties of discontinuities at the interface between different rock types in the Badong formation, China [J]. Engineering Geology, 2018, 245: 280-291

[5] WuQ, JiangY-f, TangH-m, et al.. Experimental and numerical studies on the evolution of shear behaviour and damage of natural discontinuities at the interface between different rock types [J]. Rock Mechanics and Rock Engineering, 2020, 53(8): 3721-3744

[6] ZhangX-w, LiuX-y, ChenC, et al.. Evolution of disintegration properties of granite residual soil with microstructure alteration due to wetting and drying cycles [J]. Bulletin of Engineering Geology and the Environment, 2022, 81(3): 93

[7] TianB-g, ChengQ, TangC-s, et al.. Effects of compaction state on desiccation cracking behaviour of a clayey soil subjected to wetting-drying cycles [J]. Engineering Geology, 2022, 302: 106650

[8] WuQ, LiuY-x, TangH-m, et al.. Experimental study of the influence of wetting and drying cycles on the strength of intact rock samples from a red stratum in the Three Gorges Reservoir area [J]. Engineering Geology, 2023, 314: 107013

[9] ZhangX-w, LiuX-y, ChenC, et al.. Engineering geology of residual soil derived from mudstone in Zimbabwe [J]. Engineering Geology, 2020, 277: 105785

[10] YangY-l, ZhangT, LiuS-y, et al.. Mechanical properties and deterioration mechanism of remolded carbonaceous mudstone exposed to wetting-drying cycles [J]. Rock Mechanics and Rock Engineering, 2022, 55(6): 3769-3780

[11] YuF, TongK-w, FuZ-h, et al.. Multi-scale deformation characteristics and mechanism of red-bed mudstone in dry-wet environment [J]. Frontiers in Earth Science, 2022, 10: 974707

[12] ZengZ-x, KongL-w, WangM, et al.. Assessment of engineering behaviour of an intensely weathered swelling mudstone under full range of seasonal variation and the relationships among measured parameters [J]. Canadian Geotechnical Journal, 2018, 55(12): 1837-1849

[13] ZengL, QiuJ, KuangB, et al.. Strength characteristics and deterioration mechanism of pre-disintegrated carbonaceous mudstone in wetting and drying cycles [J]. Journal of Central South University (Science and Technology), 2023, 54(9): 3635-3646(in Chinese)

[14] ZhangX W, KongL W, CuiX L, et al.. Occurrence characteristics of free iron oxides in soil microstructure: Evidence from XRD, SEM and EDS [J]. Bulletin of Engineering Geology and the Environment, 2016, 75(4): 1493-1503

[15] WuJ, LiuL, DengY-f, et al.. Use of recycled gypsum in the cement-based stabilization of very soft clays and its micro-mechanism [J]. Journal of Rock Mechanics and Geotechnical Engineering, 2022, 14(3): 909-921

[16] Ojeda-MagañaB, Quintanilla-DomínguezJ, RuelasR, et al.. Identification of pore spaces in 3D CT soil images using PFCM partitional clustering [J]. Geoderma, 2014, 217–218: 90-101

[17] RaynaudS, FabreD, MazerolleF, et al.. Analysis of the internal structure of rocks and characterization of mechanical deformation by a non-destructive method: X-ray tomodensitometry [J]. Tectonophysics, 1989, 159(1–2): 149-159

[18] KjellsenK O. Heat curing and post-heat curing regimes of high-performance concrete: Influence on microstructure and C-S-H composition [J]. Cement and Concrete Research, 1996, 26(2): 295-307

[19] LothenbachB, WinnefeldF, AlderC, et al.. Effect of temperature on the pore solution, microstructure and hydration products of Portland cement pastes [J]. Cement and Concrete Research, 2007, 37(4): 483-491

[20] GuoY-z, ChenX-d, NingY-j, et al.. Pore structure of steam cured high volume mineral admixture mortar based on X-CT technology [J]. Journal of Building Materials, 2022, 25(9): 885-892(in Chinese)

[21] SunY-l, TangL-sheng. Use of X-ray computed tomography to study structures and particle contacts of granite residual soil [J]. Journal of Central South University, 2019, 26(4): 938-954

[22] ZhangZ-h, WeiW, ZhangJ, et al.. Determining method of multiscale fractal dimension of red bed sandstone pores based on CT scanning [J]. Bulletin of Geological Science and Technology, 2022, 41(3): 254-263

[23] AnR, KongL-w, ZhangX-w, et al.. Effects of dry-wet cycles on three-dimensional pore structure and permeability characteristics of granite residual soil using X-ray micro computed tomography [J]. Journal of Rock Mechanics and Geotechnical Engineering, 2022, 14(3): 851-860

[24] YasunA S. Capability of pocket penetrometer to evaluate unconfined compressive strength of Baghdad clayey soil [J]. Al-Nahrain Journal for Engineering Sciences, 2018, 21(1): 66

[25] CaiP-c, QueY, JiangZ-l, et al.. 3D quantitative characterization and flow simulation of granite residual soil based on CT scanning [J]. Scientia Sinica (Technologica), 2022, 52(7): 1065-1082

[26] BirdM B, ButlerS L, HawkesC D, et al.. Numerical modeling of fluid and electrical currents through geometries based on synchrotron X-ray tomographic images of reservoir rocks using Avizo and COMSOL [J]. Computers & Geosciences, 2014, 73: 6-16

[27] YuH-t, LiuZ-b, ZhangY, et al.. The disintegration mechanism analysis of soft rock due to water intrusion based on discrete element method [J]. Computers & Geosciences, 2023, 171: 105289

[28] SinghA, Regenauer-LiebK, WalshS D C, et al.. On representative elementary volumes of grayscale micro-CT images of porous media [J]. Geophysical Research Letters, 2020, 47(15): e2020GL088594

[29] JacksonS J, LinQ, KrevorS. Representative elementary volumes, hysteresis, and heterogeneity in multiphase flow from the pore to continuum scale [J]. Water Resources Research, 2020, 56(6): e2019WR026396

[30] DeB W, BultreysT, DerluynH, et al.. Comparison between traditional laboratory tests, permeability measurements and CT-based fluid flow modelling for cultural heritage applications [J]. Science of the Total Environment, 2016, 554: 102-112

[31] GaoL, LiuM-x, WangZ-q, et al.. Correction of texture depth of porous asphalt pavement based on CT scanning technique [J]. Construction and Building Materials, 2019, 200: 514-520

[32] MongaO, NdeyeN F, François DelerueJ. Representing geometric structures in 3D tomography soil images: Application to pore-space modeling [J]. Computers & Geosciences, 2007, 33(9): 1140-1161

[33] ZhangZ-h, LiuW, HanL, et al.. Disintegration behavior of strongly weathered purple mudstone in drawdown area of Three Gorges Reservoir, China [J]. Geomorphology, 2018, 315: 68-79

[34] ZhaoY-x, ZhuG-p, DongY-h, et al.. Comparison of low-field NMR and microfocus X-ray computed tomography in fractal characterization of pores in artificial cores [J]. Fuel, 2017, 210: 217-226

[35] BaiY-f, QinY, LuX-r, et al.. Fractal dimension of particle-size distribution and their relationships with alkalinity properties of soils in the western Songnen Plain, China [J]. Scientific Reports, 2020, 10(1): 20603

[36] FengQ, HouS-j, LiuW-w, et al.. Study on the simulation method and mesoscopic characteristics of rock freeze-thaw damage [J]. Computers and Geotechnics, 2023, 153: 105038

[37] KenyonW E. Nuclear magnetic resonance as petrophysical measurement [J]. International Journal of Radiation Applications and Instrumentation, 1992, 6: 153-171

[38] JuY, YangY-m, MaoY-z, et al.. Laboratory investigation on mechanisms of stress wave propagations in porous media [J]. Science in China Series E: Technological Sciences, 2009, 52(5): 1374-1389

[39] YangY-w, WangB-w, YuanQ-m, et al.. Characterization, factors, and fractal dimension of pore structure of fly ash-based geopolymers [J]. Journal of Materials Research and Technology, 2023, 26: 3395-3407

[40] FangY-m, LiuHui. Probabilistic concentration prediction of PM_2.5 in subway stations based on multiresolution elastic-gated attention mechanism and Gaussian mixture model [J]. Journal of Central South University, 2023, 30(8): 2818-2832

[41] MasonG, MorrowN R. Capillary behavior of a perfectly wetting liquid in irregular triangular tubes [J]. Journal of Colloid and Interface Science, 1991, 141(1): 262-274

[42] TangC-s, ShiB, LiuC, et al.. Developing law and morphological analysis of shrinkage cracks of clayey soil under different temperatures [J]. Chinese Journal of Geotechnical Engineering, 2007, 29(5): 743-749(in Chinese)

[43] FuY-y, LiuZ-h, ZengL, et al.. Seepage characteristics test of carbonaceous mudstone soil-rock mixture considering rock content and rainfall infiltration angle [J]. Journal of Central South University, 2023, 30(10): 3467-3480

[44] GeJ-g, YanX-c, LeiY-p, et al.. A detailed analysis on the microstructure and compressive properties of selective laser melted Ti6Al4V lattice structures [J]. Materials & Design, 2021, 198: 109292

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