Strength of Discontinuous Rocks in Direct Shear

Lajtai, E.Z.

doi:10.1680/geot.1969.19.2.218

Cited by 154 publications

(68 citation statements)

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“…Laijtai performed the direct shear test on the intermittent jointed rock mass, and the composite damage theory was put forward [13]. Based on the equivalent rock mass (ERM) technique, Zhou et al performed the triaxial compression simulation on the jointed rock mass using the PFC 3D software [14].…”

Section: Introductionmentioning

confidence: 99%

Simulation Study on Strength and Failure Characteristics for Granite with a Set of Cross‐Joints of Different Lengths

Yin

Chen

Liu

et al. 2018

Advances in Civil Engineering

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e strength and failure characteristics for granite specimen with a set of cross-joints of different lengths were studied using PFC 2D software. e results show that when the included angle of α between the main joint and loading direction is 30°or 45°, no matter what the included angle of β between main and secondary joints is, the main joint controls crack propagation and failure of granite specimen, which occurs the shear failure propagating from main joint tips, and the corresponding uniaxial compressive strength is low. Meanwhile, the secondary joint is the key joint for crack propagation and failure at α of 0°and 90°except when β is 90°. e granite specimen occurs the shear failure propagating from secondary joint tips. And, the shear failure crossing upper tips of main and secondary joints is found at α of 0°or 90°and β of 90°. eir uniaxial compressive strengths are large. Also, the combined actions of main and secondary joints determine crack propagation and failure at α of 60°except when β is 90°. e granite specimen occurs the hybrid failure, including shear failure propagating from main joint tips and tensile failure propagating from main and secondary joints center or secondary joint tips. And, when α is 60°and β is 90°, the granite specimen occurs the shear failure along secondary joint plane direction, and its uniaxial compressive strength is small. Generally, when α or β is a fixed value, the uniaxial compressive strength firstly decreases and then increases with the increase of β or α. Additionally, when α is 60°and β > 45°, the uniaxial compressive strength represents a decreasing trend. e uniaxial compressive strength at α and β between 30°a nd 60°is generally small. Finally, the microdisplacement field distributions of granite specimen were discussed.

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Section: Introductionmentioning

confidence: 99%

Simulation Study on Strength and Failure Characteristics for Granite with a Set of Cross‐Joints of Different Lengths

Yin

Chen

Liu

et al. 2018

Advances in Civil Engineering

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Section: Figmentioning

confidence: 99%

“…[6,7]). Lajtai [8] performed direct shear test on natural rock specimens with two parallel slots, tensile wing cracks were found to first appear at the tips of horizontal joints, followed by the secondary shear cracks propagating towards the opposite joint. Also he observed that the failure mode changed with increasing normal stress; he suggested a composite failure envelope to describe the transition from the tensile strength of the intact material to the residual strength of the discontinuities.…”

Section: Figmentioning

confidence: 99%

Sliding Phenomena in Intermittent Rock Joint

Sarfarazi¹,

Schubert²

2016

Period. Polytech. Civil Eng.

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“…Intermediate principal stress slightly affected the strength of rock mass when such stress occurred parallel to the joint. Laijtai [4] performed the direct shear test to intermittent jointed rock mass, proposed composite damage theory, and found that body strength was a product of the rock block and joint contribution. Niu et al [6] used the numerical method to examine the sensitivity of jointed rock mass to various factors.…”

Section: State Of the Artmentioning

confidence: 99%

Simulation analysis on the strength and acoustic emission characteristics of jointed rock mass

Wen

Wang

et al. 2016

Teh. vjesn.

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Original scientific paper To analyse the influence of joint angle, number and spacing on the strength and acoustic emission (AE) characteristics of rock mass, the uniaxial compression model of rock specimens was established using the micro particle flow PFC2D software platform. The intact rock parameters were determined via trial and error, joints with different angles, numbers and spacing were prefabricated in the model, and a compression test was performed using the displacement control method. The compressive strength, elastic modulus, and AE time characteristics of the rock specimens increased, decreased, and then increased again along with increasing joint angle. The AE characteristics at joint angles 0°, 15°, 30° and 90° were consistent with those of the intact rock specimens, while the 45° ÷ 75° joint angle showed relatively discrete AE characteristics. A larger number of joints corresponded to lower uniaxial compressive strength, elastic modulus, and AE intensity. However, the time and strain range of the obvious AE were not significant. The compressive strength and AE signal intensity of the rock specimens increased along with joint spacing, but the AE triggering time did not show obvious changes. Uniaxial compression tests were performed via numerical simulation to avoid the non-homogeneous and discrete effects from the indoor test and to reflect accurately the influence of joint angle, number, and spacing on the strength and AE characteristics of rock mass. The results can help in generating reliable criteria for predicting the instability of engineering rock mass. Keywords: acoustic emission; intensity; joint angle; joint number; joint spacing; jointed rock mass Simulacijska analiza čvrstoće i karakteristika akustičke emisije raspucale stijenske maseIzvorni znanstveni članak Kako bi se analizirao utjecaj kuta, broja i raspona raspukline na čvrstoću i karakteristike akustičke emisije (AE) stijenske mase, postavljen je jednoosni kompresijski model uzoraka stijene uz primjenu PFC2D računalne platforme za protok mikro čestica. Metodom pokusa i pogreške određeni su originalni parametri stijene, u modelu su unaprijed izvedene raspukline različitih kutova, brojeva i razmaka, te je provedeno ispitivanje na pritisak metodom praćenja pomaka. Tlačna čvrstoća, modul elastičnosti i vremenske karakteristike AE uzoraka stijene su se povećali, smanjili te ponovo povećali kako se povećavao kut raspukline. Karakteristike AE kod raspukline kutova 0°, 15°, 30° i 90° bile su u skladu s onima kod originalnih uzoraka stijene, dok su se kod kuta raspukline od 45° ÷ 75° pojavile relativno diskretne karakteristike AE. Veći broj raspuklina podudarao se u nižoj jednoosnoj tlačnoj čvrstoći, modulu elastičnosti i intenzitetu AE. Međutim, nije došlo do značajne promjene u vremenu i veličini deformacije. Tlačna čvrstoća i intenzitet signala AE uzoraka stijene porasli su s povećanjem razmaka raspukline, ali se to nije pokazalo na pokazivaču vremena AE. Jednoosna ispitivanja kompresije provedena su numeričkom simulacijom kako bi se i...

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Strength of Discontinuous Rocks in Direct Shear

Cited by 154 publications

References 1 publication

Simulation Study on Strength and Failure Characteristics for Granite with a Set of Cross‐Joints of Different Lengths

Simulation Study on Strength and Failure Characteristics for Granite with a Set of Cross‐Joints of Different Lengths

Sliding Phenomena in Intermittent Rock Joint

Simulation analysis on the strength and acoustic emission characteristics of jointed rock mass

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