Wyniki wyszukiwania - BazTech

Ograniczanie wyników

2 Archives of Civil and Mechanical Engineering

2 2018

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Mechanical behavior of an opening in a jointed rock-like specimen under uniaxial loading: Experimental studies and particle mechanics approach

Cao R. H., Cao P., Lin H., Ma G. W., Fan X., Xiong X. G.

Archives of Civil and Mechanical Engineering

2018

Vol. 18, no. 1

198--214

Generally, in many cases of rock engineering, the openings often constructed in rock-mass containing non-persistent joints. However, comparing with the previous works, few studies investigate the failure or damage due to the crack propagation and coalescence around an opening. Based on the uniaxial compression tests and particle flow code (PFC) the interaction effect of opening and joints on the crack coalescence behavior around an opening are investigated in this study. From the view of experimental and numerical results, strength parameters are mainly effected by joints (inclination and distance). Specifically, the uniaxial compressive strength of jointed specimen (UCSJ) and elastic modulus of jointed specimen (EJ) of specimens decrease for 0° ≤ α ≤ 45° and increase for α > 45°. UCSJ and EJ increases with increasing joint distance (d) for all joint inclination angel (α) values, with the highest and lowest strengths obtained for d = 50 mm and d = 20 mm, respectively. The opening has a great influence on the failure mode of jointed specimen. Unlike previous results, in this study, jointed specimens present four new kinds of failure modes: Mode-I (horizontally symmetrical splitting failure); Mode-II (stepped failure at opening sides); Mode-III (failure through a plane); Mode-IV (mixed failure). The strength parameters and failure modes in the numerically simulated and experimental results are in good agreement, and the results are expected to be useful in predicting the stability of an opening in a non-persistently jointed mass.

Failure characteristics of jointed rock-like material containing multi-joints under a compressive-shear test: Experimental and numerical analyses

Cao R. H., Cao P., Lin H., Ma G. W., Zhang C. Y., Jiang C.

Archives of Civil and Mechanical Engineering

2018

Vol. 18, no. 3

784--798

Extensive efforts have been made to gain a better understanding of the failure behaviour of rocks and rock-like materials, but crack propagation and failure processes under compressive-shear loading have not yet been comprehensively investigated. To address this area of research, the peak shear strengths (τ) and failure processes of specimens with multiple joints are studied by lab testing and particle flow code (PFC2D). Four types of failure modes are observed: (a) shear failure through a plane (Mode-I), (b) intact shear failure (Mode-II), (c) oblique shear crack connection failure (Mode-III), and (d) stepped path failure (Mode-IV). The failure mode gradually transformed to Mode-III as α (joint inclination angle) increases from 0° to 90° in the specimens. In addition, with increasing joint distance (d) in the specimens, the failure mode changes to Mode-II. As the non-overlapping length between joints (c) in the specimens increases, the failure mode changes to Mode-IV. The joint geometry has a major influence on the shear strength of the jointed specimens. The peak shear strength of specimens with different joint inclination angles is obtained when α = 45°. Additionally, the peak shear strength increases as the joint distance (d) and non-overlapping length (c) increase.