Development of an automated servo-controlled direct shear apparatus applying a constant normal stiffness condition

International Journal of Rock Mechanics and Mining Sciences

Koyama

et al. 2008

202

110

Section: Test Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Experimental study of the hydro-mechanical behavior of rock joints using a parallel-plate model containing contact areas and artificial fractures

International Journal of Rock Mechanics and Mining Sciences

Koyama

et al. 2008

202

110

“…Since the 1960s, the shear behavior of rock joints has been the focus of many studies, and many achievements have been made [1][2][3][4][5][6][7][8][9]. In recent years, rock bolts have been widely used in engineering due to their convenience, affordability, and reliability.…”

Section: Introductionmentioning

confidence: 99%

Macro-Micro Failure Mechanisms and Damage Modeling of a Bolted Rock Joint

Wang

Zhang

Advances in Materials Science and Engineering

et al. 2017

The anchoring mechanism of a bolted joint subjected to a shear load was investigated using a bilinear constitutive model via the inner-embedded FISH language of particle flow code based on the discrete element method. The influences of the anchoring system on the macro-/micromechanical response were studied by varying the inclination angle of the bolt. The results indicate a clear relationship between the mechanical response of a bolted rock joint and the mechanical properties of the anchoring angle. By optimizing the anchorage angle, the peak strength can be increased by nearly 50% relative to that at an anchorage angle of 90 ∘ . The optimal anchorage angle ranges from 45 ∘ to 75 ∘ . The damage mechanism at the optimal anchorage angle joint is revealed from a macroscopic mechanical perspective. The concentration of the contact force between disks will appear in the joint and around the bolt, resulting in crack initiation. These cracks are mainly tensile cracks, which are consistent with the formation mechanism for compression-induced tensile cracks. Therefore, the macroscopic peak shear stress in the joint and the microscopic damage to the anchoring system should be considered when determining the optimal anchoring angle to reinforce a jointed rock mass.

“…Comparing with the rock matrix, the pre-existing discontinuities have a more significant influence on the macro-mechanical behavior of bedrock. The mechanical properties of discontinuities were estimated by using the test approaches reported by Li et al (2010) and Jiang et al (2004). Normal loading tests were carried out on fractured rock samples (width × height × length = 100 × 100 × 200 mm) with and without single natural discontinuities to acquire the total normal displacement u t and the intact normal displacement u i respectively.…”

Section: Properties Of Bedrockmentioning

confidence: 99%

Estimation of dynamic behaviors of bedrock foundation subjected to seismic loads based on FEM and DEM simulations

Yang

et al. 2013

KSCE J Civ Eng

Seismic behavior of bedrock foundation remains as one of the most fundamental and important problems concerning the stability and safety of nuclear power plants. The dynamic FEM (Finite Element Method) is commonly utilized in analyzing the seismic responses of bedrock; while in recent decades, the DEM (Distinct Element Method) has attracted more and more attentions, which has a better capability of simulating the sliding and separation of discontinuities in dynamic simulations. In this study, the FEM and DEM were adopted to investigate the seismic behavior of the bedrock of a nuclear power plant located in Japan, and the differences between the two methods in dynamic simulations were illuminated. Simulation results using FEM and DEM models without discontinuities agree well with each other, exhibiting an amplification effect of intact bedrock on the seismic wave propagation. Numerical simulation results obtained from the models containing faults give similar responses of bedrock to the input seismic waves; however, the FEM model underestimates the weakening effect of discontinuities on the propagation of seismic waves due to that it cannot represent well the large deformational behavior of discontinuities. When large deformation happens due to large seismic loads, the DEM can be regarded as a better method in seismic response evaluations of bedrock with discontinuities.