Shear Performance of Rock Joint Reinforced by Fully Encapsulated Rock Bolt Under Cyclic Loading Condition

Wu, Xuezhen; Jiang, Yujing; Gong, Bin; Guan, Zhongguo; Deng, Tao

doi:10.1007/s00603-018-1698-4

Cited by 48 publications

(10 citation statements)

References 30 publications

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“…Bolts are widely used in major projects such as steep slopes and tunnels as an important means of reinforcing the fractured rock masses [15][16][17][18]. Many scholars have conducted extensive research on the anchoring mechanism of bolts in rock masses and achieved many meaningful results [19][20][21][22][23][24][25][26][27]. Ge and Liu [28] studied the effects of different bolt angles, material properties, and friction angles on the shear strength of the joint and proposed a formula for estimating the shear strength of the bolted joint and the optimal anchor installation angle.…”

Section: Introductionmentioning

confidence: 99%

Anchor Stress and Deformation of the Bolted Joint under Shearing

Lin

Zhu

Yang

et al. 2020

Advances in Civil Engineering

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Bolts are widely used in rock mass engineering, wherein the bolt support improves the safety and stability of the rock mass. To reveal the mechanical behavior of the bolt and failure mechanism of the bolted joint in the shearing process, a direct shear test was conducted by changing the state of grouting, number of bolt, and inclination angle of the bolt. The change in the axial force of the anchor in the shearing process was evaluated by conducting a strain gauge test, and the mechanical behavior of the bolt under the external force was studied. The results showed that under the same normal stress, the yield displacement of the bolt decreased and the stiffness of the joint gradually increased with increased number of bolts. At the same number of bolts, their yield displacement increased with increased normal stress. Analysis further revealed that grouting on the joint improved the force condition of the bolt, increased the yield displacement of the bolt, and coordinated the deformation of the grouting body and bolt, thereby improving the shear strength of the joint. Lastly, when the anchor angles differed, the axial pulling resistance of the anchor changed, and the yield displacement of the anchor with 45° inclination was <90°. The yield displacement of the bolt showed that the supporting effect of the bolt with a 45° inclination was better than that of the bolt with a 90° inclination.

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Section: Introductionmentioning

confidence: 99%

Anchor Stress and Deformation of the Bolted Joint under Shearing

Lin

Zhu

Yang

et al. 2020

Advances in Civil Engineering

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“…Having high mechanical properties when completely cured as well as low viscosity, which enables it to penetrate into the finest seams, cracks, and pores in soils and fill them homogeneously, along with undisputed adhesion capability, makes grouting a unique strategy to increase the performance of geotechnical structures [ 8 , 9 , 10 , 11 ]. Cement has been used as the base material in grout mixtures for a long time due to ease in accessibility and price efficiency in addition to its convenient post-curing strength [ 12 , 13 , 14 , 15 , 16 , 17 , 18 ]. However, despite the beneficial traits cement-based grouts provide, there are a few considerable drawbacks that do not allow cement grouts to be applied in every situation.…”

Section: Introductionmentioning

confidence: 99%

Investigating the Effects of Cement and Polymer Grouting on the Shear Behavior of Rock Joints

et al. 2022

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This study carried out a comparison between cement grouting and chemical grouting, using epoxy and polyurethane, with respect to their effects on the shear behavior of joints. Joint replicas, with three different grades of surface roughness, were molded and grouted by means of cement and epoxy grouts of various mixtures. To investigate their shear behavior, samples were subjected to direct shear tests under constant normal load (CNL) condition. According to the results obtained, grouting improves the overall shear strength of the rock joints. All the grouted samples yielded higher maximum and residual shear strength in comparison with the non-grouted joint. Grouting resulted in an improvement in the cohesion of all the samples. However, a fall in friction angle by 5.26° in the sample with JRC of nine was observed, yet it was reduced by 2.36° and 3.26° for joints with JRC of 14 and 19, respectively. Cement grouts were found to have a more brittle behavior, whereas the chemical grouts were more ductile. Higher amounts of cement used in the grout mixture do not provide as much cohesion and only increase the brittleness of the grout. As a result of being more brittle, cement grout breaks into small pieces and joint planes are in better contact during shearing; consequently, there would be less of a fall in friction angle as opposed to epoxy grout whose ductile characteristic prevents grout chipping; therefore, joint planes are not in contact and a greater fall in the friction angle occurs. There was no noticeable change in the cohesion of the larger grouted joints. However, the friction angle of both natural and grouted joints increased in the larger joint. This can be related to the distribution of random peaks and valleys on the joint surface, which increases with the joint size.

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“…The shear stress, normal stress and normal displacement for rock joints (infilled) under constant normal stiffness was increased with increasing shear rate as presented by Guansheng et al (2020). Wu et al (2019) conducted cyclic shear load on bolted rock joints for small and large displacements. When displacement was large; the shear strength reduction of bolted joints was comparable to the unbolted joint.…”

Section: Introductionmentioning

confidence: 99%

Effect of Load Frequency and Amplitude of Displacement on Soft Rock Joints under Cyclic Shear loads

Niktabar

Rao

Shrivastava

et al. 2022

Preprint

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A series of cyclic shear tests was conducted on soft synthetic rock joints with 30°- 30° asperities. Large scale shear apparatus was used in the experiments to investigate effects of shear load frequency and amplitude of displacement on the joint behaviour. Varying load frequencies (0.01, 0.05 and 0.1 Hz,) and displacement amplitudes (±4, ±6, and ±8 mm) for three different normal stresses (0.1, 0.5 and 1 MPa) were applied. The results indicated that the first peak shear stress on the joint is significantly influenced by the frequency of cyclic shear load and subsequent peaks of shear stress are largely influenced by the amplitude of displacement. Reduction in peak shear stress at higher frequency of load is greater than the reduction at lower frequency of load under cyclic movements. Shear mechanism on the joint asperities at low normal stress demonstrate asperity diminishing does not depend on load direction at high frequency. Whereas, at low frequency of loads, it depends on direction of starting cyclic shear load. Low amplitude of displacement has no effect on asperity deformation under cyclic loads. As the amplitude rises, the diminishing of asperities increases significantly. Shear mechanism and asperity diminishing at low normal stress is similar for the both higher amplitude of displacement and lower frequency of load. Comparison of shear strength envelopes indicated an opposite behaviour of the joint at varying load frequencies and displacement amplitudes.

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Shear Performance of Rock Joint Reinforced by Fully Encapsulated Rock Bolt Under Cyclic Loading Condition

Cited by 48 publications

References 30 publications

Anchor Stress and Deformation of the Bolted Joint under Shearing

Anchor Stress and Deformation of the Bolted Joint under Shearing

Investigating the Effects of Cement and Polymer Grouting on the Shear Behavior of Rock Joints

Effect of Load Frequency and Amplitude of Displacement on Soft Rock Joints under Cyclic Shear loads

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