Experimental and Numerical Studies on the Evolution of Shear Behaviour and Damage of Natural Discontinuities at the Interface Between Different Rock Types

Wu, Qiong; Jiang, Yaofei; Tang, Huiming; Luo, Hui; Wang, Xiaohan; Kang, Jintao; Zhang, Shu; Xue, Yi; Li, Fan

doi:10.1007/s00603-020-02129-9

Cited by 32 publications

(8 citation statements)

References 47 publications

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“…For the studied three types of DDJM samples, deterioration of the weak half material is more severe than the hard half material. During the shearing process of DDJM samples, particle failures occur in the two joint walls with the weak half being more severe (Wu et al 2020). The decrease in cementation and friction among mineral particles in the weak half of DDJM plays a major role.…”

Section: Weakening Mechanism Of Ddjmmentioning

confidence: 99%

Experimental Investigation on Weakening of Discontinuities at the Interface Between Different Rock Types Induced by Wetting and Drying Cycles

Meng

Tang

et al. 2022

Rock Mech Rock Eng

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Recent research has paid little attention to weakening of discontinuities with different joint wall material (DDJM) induced by wetting and drying cycles. Experimental investigations were conducted to examine the effects of wetting-drying cycles on weakening of three typical types of natural planar DDJM collected from a sliding-prone formation in the Three Gorges reservoir region of China. Deterioration of the corresponding four types of discontinuities with identical joint wall material (DIJM) were also been studied for comparison. The weakening laws of DDJM were revealed from macro-and microperspectives by testing on mineral compositions, microstructures and water absorption rate of joint walls as well as shear strength of discontinuities. The results indicate that the repeated wetting-drying cycles lead to obvious changes in microstructure and increases of macro water absorption rate for the studied joint walls with the changing degree closely related to their clay mineral contents; the peak shear strengths of DDJM gradually decreases with the wetting and drying cycles for a certain normal stress with the weakening rate between that of the DIJM with two joint wall materials of the DDJM, while closer to that of DIJM with the weak half materials of the DDJM; significant correlations have been found between the variation coefficient of rock microstructure of joint walls and the macrodeterioration coefficient of DDJM; the changing rates of multiscale parameters before and after six wetting-drying cycles vary obviously, indicating the weakening is slowed down after six wetting-drying cycles for the studied discontinuities. Highlights• Effects of wetting-drying cycles on weakening discontinuities with different joint wall material were studied. • Deterioration of the discontinuities with identical joint wall material were also been investigated for comparison. • The weakening laws were revealed from macro and micro perspectives.• Significant correlations have been found between the variation coefficient of microstructure of joint walls and themacro deterioration coefficient. • The results could provide a basis to better understand the stability evolution of rock slopes with soft and hardrock interbedded. KeywordsDiscontinuities with different joint wall material (DDJM) • Discontinuities with identical joint wall material (DIJM) • Weakening of discontinuities • Wetting and drying cycles • Shear strength • Microstructure • Multi-scale deterioration * Huiming Tang

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Section: Weakening Mechanism Of Ddjmmentioning

confidence: 99%

Experimental Investigation on Weakening of Discontinuities at the Interface Between Different Rock Types Induced by Wetting and Drying Cycles

Meng

Tang

et al. 2022

Rock Mech Rock Eng

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“…Through laboratory tests, as the most common means to study the anchored structural plane, many scholars have carried out relevant research around rock strength [23], anchoring method [24], bolt type [25], anchorage angle [26], and joint roughness [27], and revealed the influence law of these factors on the shear mechanical properties of anchored structural plane [28,29]. According to some research [30], the irregular joint morphology is the main reason for the appearance of dilatancy. The normal displacement of rock block caused by the dilatancy will change the force condition of the bolt and then affect the shear mechanical properties of anchored structural plane.…”

Section: Introductionmentioning

confidence: 99%

Mechanical Properties and Acoustic Emission Characteristics of Anchored Structure Plane with Different JRC under Direct Shear Test

Lin

Feng

et al. 2022

Materials

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Rock mass, the heterogeneous natural material composed of rock and discontinuities, is an important part of engineering construction. Discontinuities affect the mechanical properties of natural rock mass and further threaten the stability of rock engineering. To study the failure characteristics of anchored structure plane with different JRC, jointed specimens with four different JRC were fabricated by pouring cement mortar. Specimens were tested under four different normal loads to figure out how JRC and anchorage angle affect the mechanical properties of anchored structure plane. Besides, acoustic emission (AE) testing technology was adopted to explore the AE characteristics of anchored structural plane under shearing. The results showed that there exists a positive correlation between the peak shear strength and JRC. The undulation shape of structural plane led to an obvious downward trend in the strain softening stage of the structural plane with JRC of 6–8 and 18–20. When the anchorage angle ranged from 45° to 60°, the potentiation of bolt was the most significant. Based on the AE results, the larger the normal stress, the more likely the cumulative count curves were to enter the fast growth phase before the peak. The characteristics of b-value curves are mainly related to the topography of structural planes and whether the bolt is deformed. In the direct shear test, the cumulative proportion of shear cracks was more than 85%, which is much higher than that of tensile cracks. The variation of cumulative tensile cracks goes through three stages: slow growth, rapid growth, and slow growth. Compared with the unanchored structural plane, the variation range of real-time tensile cracks of the anchored structural plane is large, and sometimes the proportion of real-time tensile cracks may reach 80%.

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“…The weakening of rock resulted from cyclic wetting and drying can be reflected in two aspects: strength variation and structure variation. Currently, the strength variation in rock can be measured by various mechanical tests [ 7 , 8 , 9 , 10 , 11 ], e.g., the uniaxial compressive test, triaxial compressive test and direct shear test. Considering that most natural rocks are in the stress state of compression, the compressive tests are more commonly used.…”

Section: Introductionmentioning

confidence: 99%

Weakening Investigation of Reservoir Rock by Coupled Uniaxial Compression, Computed Tomography and Digital Image Correlation Methods: A Case Study

Shen

Tang

Zhang

et al. 2021

Sensors

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Cyclic wetting and drying treatment is commonly used to accelerate the weakening process of reservoir rock. The weakening is reflected in strength variation and structure variation, while the latter receives less attention. Based on a series of cyclic wetting and drying tests, this study tentatively applied the uniaxial compressive test, computed tomography (CT) test and digital image correlation (DIC) test to investigate the weakening of slate in a reservoir area. Test results show that the weakening is mainly reflected in the reduction of compressive strength, followed by the decrease of ability to resist cracking and elastic deformation. The weakening seems more likely to be caused by structure variation rather than composition change. Two failure modes, e.g., splitting and splitting-tension, are concluded based on the crack paths: the splitting failure mode occurs in the highly weathered samples and the splitting-tension failure mode appears in the low-weathered samples. The transition zones of deformation are inside samples. The nephogram maps quantify the continuous deformation and correspond to the aforementioned structure variation process. This study offers comprehensive methods to the weakening investigation of slate in reservoir area and may provide qualitative reference in the stability evaluation of related slate rock slope.

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Experimental and Numerical Studies on the Evolution of Shear Behaviour and Damage of Natural Discontinuities at the Interface Between Different Rock Types

Cited by 32 publications

References 47 publications

Experimental Investigation on Weakening of Discontinuities at the Interface Between Different Rock Types Induced by Wetting and Drying Cycles

Experimental Investigation on Weakening of Discontinuities at the Interface Between Different Rock Types Induced by Wetting and Drying Cycles

Mechanical Properties and Acoustic Emission Characteristics of Anchored Structure Plane with Different JRC under Direct Shear Test

Weakening Investigation of Reservoir Rock by Coupled Uniaxial Compression, Computed Tomography and Digital Image Correlation Methods: A Case Study

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