Large-scale physical model test of 30°inclined strata was conducted to investigate the damage mechanisms during the excavation and overloading using infrared detection.The experiment results were presented with t...Large-scale physical model test of 30°inclined strata was conducted to investigate the damage mechanisms during the excavation and overloading using infrared detection.The experiment results were presented with thermal images which were divided into three stages including a full face excavation stage,a staged excavation stage,and an overloading stage.The obtained results were compared with the previously reported results from horizontal,45?,60?,and vertical strata models.Infrared temperature(IRT)for 30°inclined strata model descended with multiple fluctuations during the full-face excavation.For the staged excavation,the excavation damage zone(EDZ)showed enhanced faulting-like strips as compared in the 45?,60?,and vertical models,indicating the intensified stress redistribution occurred in the adjacent rock mass.In contrast,EDZ for the horizontal strata existed in a plastic-formed manner.During the overloading,abnormal features in the thermal images were observed preceding the coalescence of the propagating cracks.The ultimate failure of the model was due primarily to the floor heave and the roof fall.展开更多
Rectangular inclined channels prove promising for solid classification based on the principle of parti- cle differential sedimentation. In the present work, we investigated the motion characteristics of binary solids ...Rectangular inclined channels prove promising for solid classification based on the principle of parti- cle differential sedimentation. In the present work, we investigated the motion characteristics of binary solids in a modified fluidised bed （mFB） with inclined plates. We developed a theoretical model for the particle motion behaviour that accounts for the average solid volume fraction in the inclined channel and interactions between binary solids. The experimental system was designed to be consistent with the idealised theoretical arrangements to maximise the measurement accuracy. The experimental particles were mixtures of silica sand particles of sizes 425-710 i^m and 710-880/~m, respectively. Specifically, we investigated the flow hydrodynamics of the binary suspension in terms of the settling length of both par- ticle species and the bed expansion behaviour. We also analysed the utilisation factor and the separation efficiency of the mFB. The results showed that the average solid volume fraction in the inclined channel fluctuated slightly for a given total solid inventory. The utilisation factor and separation efficiency of the system decreased when increasing either the fluidisation velocity or the solid inventory. The prediction results were in good agreement with the experimental data with an absolute deviation of less than 15%.展开更多
基金supported by the National Key Research and Development Plan of China (Grant No. 2016YFC0600901)the National Natural Science Foundation of China (Grant Nos. 51374214, 51134005 & 51574248)+1 种基金the Special Fund of Basic Research and Operating of China University of Mining & Technology, Beijing (Grant No. 2009QL03)the State Scholarship Fund of China
文摘Large-scale physical model test of 30°inclined strata was conducted to investigate the damage mechanisms during the excavation and overloading using infrared detection.The experiment results were presented with thermal images which were divided into three stages including a full face excavation stage,a staged excavation stage,and an overloading stage.The obtained results were compared with the previously reported results from horizontal,45?,60?,and vertical strata models.Infrared temperature(IRT)for 30°inclined strata model descended with multiple fluctuations during the full-face excavation.For the staged excavation,the excavation damage zone(EDZ)showed enhanced faulting-like strips as compared in the 45?,60?,and vertical models,indicating the intensified stress redistribution occurred in the adjacent rock mass.In contrast,EDZ for the horizontal strata existed in a plastic-formed manner.During the overloading,abnormal features in the thermal images were observed preceding the coalescence of the propagating cracks.The ultimate failure of the model was due primarily to the floor heave and the roof fall.
文摘Rectangular inclined channels prove promising for solid classification based on the principle of parti- cle differential sedimentation. In the present work, we investigated the motion characteristics of binary solids in a modified fluidised bed （mFB） with inclined plates. We developed a theoretical model for the particle motion behaviour that accounts for the average solid volume fraction in the inclined channel and interactions between binary solids. The experimental system was designed to be consistent with the idealised theoretical arrangements to maximise the measurement accuracy. The experimental particles were mixtures of silica sand particles of sizes 425-710 i^m and 710-880/~m, respectively. Specifically, we investigated the flow hydrodynamics of the binary suspension in terms of the settling length of both par- ticle species and the bed expansion behaviour. We also analysed the utilisation factor and the separation efficiency of the mFB. The results showed that the average solid volume fraction in the inclined channel fluctuated slightly for a given total solid inventory. The utilisation factor and separation efficiency of the system decreased when increasing either the fluidisation velocity or the solid inventory. The prediction results were in good agreement with the experimental data with an absolute deviation of less than 15%.
