The strength and failure characteristics of most natural rock mass are influenced by discontinues such as fissures, joints, and weak surfaces. In the present study, the strength and failure behavior of ubiquitous- joi...The strength and failure characteristics of most natural rock mass are influenced by discontinues such as fissures, joints, and weak surfaces. In the present study, the strength and failure behavior of ubiquitous- joint rock-l!ke specimens under uniaxial loading have been investigated by DIC （digital image correlation） and discrete element numerical method （PFC2D）. The results are obtained. Firstly, the UCSJ of spec- imens with γ= 15° or 30° shows similar tendency while α goes from 0° to 75°. With γ= 45° or 60°, the UCSJ of specimens increases when α goes from 0° to 30° and decreases after α goes beyond 30°. With γ=75°, the peak UCSJ value is reached when α=0°. The UCSJ value shows an increasing trend when α goes from 60° to 75°. Secondly, the ubiquitous-joint specimens present different failure modes for various levels of α and γ（β-α）. Based on the experimental results, the failure mode of ubiquitous-joint specimens can be classified into three categories： stepped path failure, failure through parallel plane, and failure through cross plane.展开更多
Fresnel incoherent correlation holography(FINCH)is a well-established incoherent imaging technique.In FINCH,three selfinterference holograms are recorded with calculated phase differences between the two interfering,d...Fresnel incoherent correlation holography(FINCH)is a well-established incoherent imaging technique.In FINCH,three selfinterference holograms are recorded with calculated phase differences between the two interfering,differently modulated object waves and projected into a complex hologram.The object is reconstructed without the twin image and bias terms by a numerical Fresnel back propagation of the complex hologram.A modified approach to implement FINCH by a single camera shot by pre-calibrating the system involving recording of the point spread function library and reconstruction by a nonlinear cross correlation has been introduced recently.The expression of the imaging characteristics from the modulation functions in original FINCH and the modified approach by pre-calibration in spatial and polarization multiplexing schemes are reviewed.The study reveals that a reconstructing function completely independent of the function of the phase mask is required for the faithful expression of the characteristics of the modulating function in image reconstruction.In the polarization multiplexing method by non-linear cross correlation,a partial expression was observed,while in the spatial multiplexing method by non-linear cross correlation,the imaging characteristics converged towards a uniform behavior.展开更多
基金funding from Project (Nos.51474249 and 51404179) supported by National Natural Science Foundation of ChinaProject Supported by Innovation Driven Plan of Central South University of China (No.2016CX019)Project (No. SKLGDUEK1405) funded by the Open Projects of State Key Laboratory for Geo-mechanics and Deep Underground Engineering of China University of Mining and Technology,in China
文摘The strength and failure characteristics of most natural rock mass are influenced by discontinues such as fissures, joints, and weak surfaces. In the present study, the strength and failure behavior of ubiquitous- joint rock-l!ke specimens under uniaxial loading have been investigated by DIC （digital image correlation） and discrete element numerical method （PFC2D）. The results are obtained. Firstly, the UCSJ of spec- imens with γ= 15° or 30° shows similar tendency while α goes from 0° to 75°. With γ= 45° or 60°, the UCSJ of specimens increases when α goes from 0° to 30° and decreases after α goes beyond 30°. With γ=75°, the peak UCSJ value is reached when α=0°. The UCSJ value shows an increasing trend when α goes from 60° to 75°. Secondly, the ubiquitous-joint specimens present different failure modes for various levels of α and γ（β-α）. Based on the experimental results, the failure mode of ubiquitous-joint specimens can be classified into three categories： stepped path failure, failure through parallel plane, and failure through cross plane.
基金NATO grant No.SPS-985048Linkage grant No.LP190100505the Australian Research Council Discovery grant No.DP190103284。
文摘Fresnel incoherent correlation holography(FINCH)is a well-established incoherent imaging technique.In FINCH,three selfinterference holograms are recorded with calculated phase differences between the two interfering,differently modulated object waves and projected into a complex hologram.The object is reconstructed without the twin image and bias terms by a numerical Fresnel back propagation of the complex hologram.A modified approach to implement FINCH by a single camera shot by pre-calibrating the system involving recording of the point spread function library and reconstruction by a nonlinear cross correlation has been introduced recently.The expression of the imaging characteristics from the modulation functions in original FINCH and the modified approach by pre-calibration in spatial and polarization multiplexing schemes are reviewed.The study reveals that a reconstructing function completely independent of the function of the phase mask is required for the faithful expression of the characteristics of the modulating function in image reconstruction.In the polarization multiplexing method by non-linear cross correlation,a partial expression was observed,while in the spatial multiplexing method by non-linear cross correlation,the imaging characteristics converged towards a uniform behavior.
