Macro-meso fatigue failure of bimrocks with various block content subjected to multistage fatigue triaxial loads

Wang, Yu; Mao, Tianqiao; Xia, Yingjie; Li, Xiao; Yi, Xuefeng

doi:10.1016/j.ijfatigue.2022.107014

Cited by 38 publications

(28 citation statements)

References 38 publications

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“…Frost heaving force is easily formed in the interfaces, pores, and microcracks, which leads to damage propagation, aperture growth and length increase, and the bimrock structure deterioration. Besides, in geotechnical engineering, for example, mining and civil engineering, disturbed stress is inevitable in the process of rock mass construction; 25–28 the disturbed stress conditions improve the reactivation of fault bands. Although large number of attempts have been carried out on rock fracture and instability behaviors under cyclic or fatigue loads, most of the investigations are focused on fissure‐contained 29,30 or cavity‐contained rock mass 31–33 .…”

Section: Introductionmentioning

confidence: 99%

Macro‐meso damage cracking and volumetric dilatancy of fault block‐in‐matrix rocks induced by freeze–thaw‐multistage constant amplitude cyclic (F‐T‐MSCAC) loads

Wang

Cai

et al. 2022

Fatigue Fract Eng Mat Struct

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In this study, we experimentally investigated the mechanical behaviors of a fault unwelded bimrock exposed to first freeze-thaw weathering and then disturbed stress conditions. The impact of freeze-thaw damage on volumetric deformation, damage propagation, and mesoscopic instability mode was studied. Test results show that the block-matrix interface cracking easily occurs after freeze-thaw treatment. The strain rate increases with the increase of the freeze-thaw cycle, and an early instability precursor is issued from the evolution of volumetric strain rare. In addition, a coupled evolution model considering the mechanical damage and the freeze-thaw weathering damage was defined, and it was suggested that the model pattern has obviously correlation with the occurrence of freeze-thaw damage. Moreover, posttest CT scanning revealed the influence of freeze-thaw on meso-cracking and volumetric dilatancy pattern. It is found that the block contact, interlocking, occlusion, and separation contribute a lot to bimrock volumetric expansion.

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Section: Introductionmentioning

confidence: 99%

Macro‐meso damage cracking and volumetric dilatancy of fault block‐in‐matrix rocks induced by freeze–thaw‐multistage constant amplitude cyclic (F‐T‐MSCAC) loads

Wang

Cai

et al. 2022

Fatigue Fract Eng Mat Struct

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“…Here, some new terminologies are used for bimrocks, such as block-in-matrix-soils (bimsoils), 8,9 rock and soil aggregation (RSA), 10 and soil and rock mixture (SRM), 11,12 such as mélanges, coarse pyroclastic rocks, breccias, colluviums and alluviums, fault rocks, and conglomerates, etc. The static mechanical behaviors of bimrock have been widely investigated by laboratory compression tests 13 or shear tests, 14 field shear tests, 15,16 numerical tests, 17 and so forth. For the fault rocks, some scholars conducted laboratory tests to study its strength and deformation characteristics.…”

Section: Introductionmentioning

confidence: 99%

Macro‐meso fatigue damage and instability of a fault bimrock exposed to multistage cyclic triaxial loads with different confining pressure

Wang

Mao

Zhang

et al. 2022

Fatigue Fract Eng Mat Struct

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A series of cyclic triaxial tests combined with post‐test CT scanning were performed on a fault bimrock (block‐in‐matrix‐rock). The influence of confining pressure on the macro‐meso fatigue damage and instability characteristics were investigated in terms of strength, stiffness, volumetric deformation, damage evolution, and mesoscopic failure pattern. It is revealed that bimrock strength, deformation, and stiffness increase with increasing of confining pressure. A larger confining pressure leads to a lower rate of axial and volumetric strain. An early instability precursor corresponding to the strong volumetric dilatancy was issued using the strain rate than the volumetric strain. An inverted “L” and “S” shaped damage evolution pattern were revealed and modelled, and the proposed model fits well to the testing data. Post‐test 3D computed tomography scanning visualizes the multiple interface cracking behaviors and volumetric change. It is suggested that the skeleton role of blocks was strengthened and the block‐matrix interactions were influenced by the applied confining pressure.

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“…The threedimensional stress is the occurrence condition of the fractured rock mass, and the fracture dip angle is the geometric state of the fracture itself. These two aspects have mutual influence on the slurry migration in the fracture and are a pair of coupling factors [39][40][41][42][43][44]. In a word, the slurry diffusion in the fractured rock body needs to consider the slurry diffusion mechanism in the fractured rock body with different dip angles under the three-dimensional stress environment, which is the research direction that meets the needs of the project.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Grouting Seepage Characteristics of Single-Fractured Rock Masses with Different Inclination Angles under Three-Dimensional Stress

Zhu

Han

2022

Geofluids

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In underground engineering, the fracture dip angle and three-dimensional stress have great influence on the permeability and mechanical properties of fractured rock mass. Firstly, single-fracture samples with similar three-dimensional fractal dimensions and different dip angles were selected by using CT scanning technology. Then, the grouting material seepage tests under different dip angles and different three-dimensional stresses were carried out by self-developed single-fracture stress-seepage coupling true triaxial test system. The experimental data of stress-strain curve, grouting pressure, and grouting material flow rate of single-fracture specimen under different fracture dip angles and three-dimensional stress were obtained. The results show that the three-dimensional fractal dimension can be used as an index to measure the influence of fracture factors on grouting seepage test. The third principal stress σ 3 had a greater influence on the fracture width than the first principal stress σ 1 . The larger the fracture inclination, the lower the strength of the single-fracture specimen. As the third principal stress σ 3 increases, the grouting pressure increased while the grouting flow decreased. With the increase of the fracture inclination angle, the influence of σ 1 on the hydraulic conductivity became larger, while the influence of σ 3 on the hydraulic conductivity became smaller. Moreover, the expression of hydraulic conductivity of single-fracture specimen with different dip angles under three-dimensional stress was obtained by nonlinear fitting of hydraulic conductivity data.

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Macro-meso fatigue failure of bimrocks with various block content subjected to multistage fatigue triaxial loads

Cited by 38 publications

References 38 publications

Macro‐meso damage cracking and volumetric dilatancy of fault block‐in‐matrix rocks induced by freeze–thaw‐multistage constant amplitude cyclic (F‐T‐MSCAC) loads

Macro‐meso damage cracking and volumetric dilatancy of fault block‐in‐matrix rocks induced by freeze–thaw‐multistage constant amplitude cyclic (F‐T‐MSCAC) loads

Macro‐meso fatigue damage and instability of a fault bimrock exposed to multistage cyclic triaxial loads with different confining pressure

Experimental Study on Grouting Seepage Characteristics of Single-Fractured Rock Masses with Different Inclination Angles under Three-Dimensional Stress

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