Frictional behavior of sandstone fractures under forward-backward pre-peak cyclic loading

Thongprapha, Thanittha; Liapkrathok, Pittawat; Chanpen, Surasak; Fuenkajorn, Kittitep

doi:10.1016/j.jsg.2020.104106

Cited by 5 publications

(3 citation statements)

References 23 publications

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“…It was observed that the shear sliding mechanism was significant at low normal stress and that the second-order asperities were not effective during shear cycles. However, in another report for pre-peak cyclic shear loading (Thongprapha et al, 2020 [ 27 ]) with higher normal stress, the second-order asperities were diminished; subsequently, joint roughness and shear resistance were decreased. Belem et al, 2007 [ 28 ] and Belem et al, 2009 [ 29 ] investigated joint surface degradation under CNL and CNS for monotonic and cyclic shearing by laser scanning and proposed a method for the estimation of joint surface wearing based on changing normal loads.…”

Section: Introductionmentioning

confidence: 99%

Effect of Varying Normal Stiffness on Soft Rock Joints under Cyclic Shear Loads

et al. 2023

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The evaluation of changes in shear resistance on soft (or weathered) rock joints under cyclic shear loads with constant normal load (CNL) and constant normal stiffness (CNS) significantly contributes to increasing the safety and stability of rock slopes and underground structures. In this study, a series of cyclic shear tests were conducted on simulated soft rock joints with regular (15°-15°, 30°-30°) and irregular (15°-30°) asperities under different normal stiffnesses (kn). The results indicated that the first peak shear stress increases with the increase in kn up to the normal stiffness of the joints (knj). Beyond knj, no significant change was observed in the peak shear stress. The difference in peak shear stress between regular (30°-30°) and irregular joints (15°-30°) increases as kn increases. The minimum difference of peak shear stress between regular and irregular joints was observed (8.2%) under CNL and the maximum difference was found (64.3%) on knj under CNS. The difference in peak shear stress between the first and subsequent cycles significantly increases as both the joint roughness and kn increases. A new shear strength model is developed to predict peak shear stress of the joints for different kn and asperity angles under cyclic shear loads.

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Section: Introductionmentioning

confidence: 99%

Effect of Varying Normal Stiffness on Soft Rock Joints under Cyclic Shear Loads

et al. 2023

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“…Regarding rock fatigue damage, significant attention has been paid to maximum stress [5], stress amplitudes [6][7], dynamic frequency [8], loading waveforms [9][10], and strain rates [11]. Several fatigue models were proposed according to ultrasonic velocity [12], rock deformation [13][14], elastic modulus [15], energy dissipation [16][17], acoustic emission characteristics [18], and the load-unload response ratio (LURR) [19].…”

Section: Introductionmentioning

confidence: 99%

Volumetric deformation and damage evolution of Tibet interbedded skarn under multistage constant-amplitude-cyclic loading

Zhu

Karakus

He³

et al. 2022

International Journal of Rock Mechanics and Mining Sciences

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“…When it comes to the influence of loading rate on mechanical responses of rock, scholars have carried out a lot of research work on strength, deformation and failure characteristics, and achieved fruitful research results (Hashiba and Fukui, 2015;Meng et al, 2016;Imani et al, 2017;Feng et al, 2018;Kang et al, 2019;Thongprapha et al, 2020;Tang et al, 2021;Lu et al, 2022;Tie et al, 2023). It has been proven that loading rate, as an important factor, can significantly affect the mechanical characteristics of rock.…”

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confidence: 99%

Experimental study on mechanical and acoustic emission characteristics of sedimentary sandstone under different loading rates

Li,

Feng,

Yue

et al. 2023

Front. Earth Sci.

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In the field of rock engineering, complexity of stress environment is an important factor affecting its stability. Thus, in view of fracture mechanism of rock under different loading rates within the scope of quasi-static strain rate, four groups of uniaxial compression tests with different strain rates were carried out on sandstone specimens, and strength, deformation, failure modes and acoustic emission characteristics of specimens were compared and analyzed. Furthermore, the fracture mechanism was discussed from the perspective of fracture characteristics based on fractal dimension, crack propagation law inverted through acoustic emission b-value, and micro fracture morphology. The results showed that as the strain rate increased from 10 to 5 s−1 to 10−2 s−1, the fractal dimension of rock fragments increased, and the fractal dimension of rock fragments increased by 9.66%, 7.32%, and 3.77% successively for every 10 times increase in strain rate, which means that the equivalent size of fragments was getting smaller, and the fragmentation feature was becoming increasingly prominent. The crack propagation process based on acoustic emission b-value showed that with the increase of loading rate, the specimen entered the rapid crack propagation stage earlier, in order of 68%, 66%, 29%, and 22% of peak stress. Moreover, the microscopic fracture morphology showed that with the increase of loading rate, transgranular phenomenon was clear, and the fracture morphology changed from smooth to rough. That meant that the fracture of sandstone rock at high loading rates was mainly caused by the propagation of large cracks, which was different from the slow process of initiation, convergence and re-propagation of small cracks at low strain rates.

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Frictional behavior of sandstone fractures under forward-backward pre-peak cyclic loading

Cited by 5 publications

References 23 publications

Effect of Varying Normal Stiffness on Soft Rock Joints under Cyclic Shear Loads

Effect of Varying Normal Stiffness on Soft Rock Joints under Cyclic Shear Loads

Volumetric deformation and damage evolution of Tibet interbedded skarn under multistage constant-amplitude-cyclic loading

Experimental study on mechanical and acoustic emission characteristics of sedimentary sandstone under different loading rates

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