Bonded blockmodel(BBM)has shownpotential in replicating rockmass behavior aswell as the rockesupport interactionmechanism,but their practical application is limited totwo dimensions due to the high associated computat...Bonded blockmodel(BBM)has shownpotential in replicating rockmass behavior aswell as the rockesupport interactionmechanism,but their practical application is limited totwo dimensions due to the high associated computational demand.To allow for the use of BBM in simulating three-dimensional(3D)problems,this study proposes an integrated 3D continuumetwo-dimensional(2D)discontinuum approach,in context of rock pillars.A cross-section of a granite pillar was simulated using a BBM with a load path from a calibrated mine-scale FLAC^(3D)model.Pillar support as employed in the mine was also incorporated in different stages during the simulation.Themodel was calibrated by varying the input parameters until the displacements at six locations within the pillarmatchedthosemeasuredby amulti-point borehole extensometer(MPBX)inthe field.The calibratedmodel was subsequently used to understand how the support and load path influenced the damage evolution in the pillar.The shear component of the load pathwas found to have amajor effect on the severity and extent of the damaged regions.When the support density was increased in the model,the lateral displacements along the pillar walls were significantly suppressed in a somewhat unpredictable manner.Thiswas explained by the interaction between the supports and the damaged regions at the corners,which ultimately modified the stresses along the pillar periphery.The amount of displacement reduction obtained by increasing the support density illustrates the potential of BBMto be used as a support design tool.展开更多
Chiral supramolecules prepared by the additive-driven self-assembly of block copolymers provide a facile method to construct helical nanostructures. In this study, we investigated the chiral transfer from chiral tarta...Chiral supramolecules prepared by the additive-driven self-assembly of block copolymers provide a facile method to construct helical nanostructures. In this study, we investigated the chiral transfer from chiral tartaric acid to poly（styrene）-b-poly（ethylene oxide） using small-angle X-ray scattering,transmission electron microscopy, circular dichroism, and vibrational circular dichroism. The results showed that the chirality was transferred to both the segments of block copolymer irrespective of the interaction with the chiral additives and formation of helical phase structure. However, the chirality transfer was carried out using different methods： for poly（ethylene oxide） segments, the chirality transfer was carried out via direct hydrogen bond formation; for polystyrene segments, the chirality transfer was carried out via the cooperative motion of block copolymers during the thermal annealing.展开更多
基金The research conducted for this study was funded by the National Institute for Occupational Safety and Health(NIOSH)under Grant No.200-2016-90154.
文摘Bonded blockmodel(BBM)has shownpotential in replicating rockmass behavior aswell as the rockesupport interactionmechanism,but their practical application is limited totwo dimensions due to the high associated computational demand.To allow for the use of BBM in simulating three-dimensional(3D)problems,this study proposes an integrated 3D continuumetwo-dimensional(2D)discontinuum approach,in context of rock pillars.A cross-section of a granite pillar was simulated using a BBM with a load path from a calibrated mine-scale FLAC^(3D)model.Pillar support as employed in the mine was also incorporated in different stages during the simulation.Themodel was calibrated by varying the input parameters until the displacements at six locations within the pillarmatchedthosemeasuredby amulti-point borehole extensometer(MPBX)inthe field.The calibratedmodel was subsequently used to understand how the support and load path influenced the damage evolution in the pillar.The shear component of the load pathwas found to have amajor effect on the severity and extent of the damaged regions.When the support density was increased in the model,the lateral displacements along the pillar walls were significantly suppressed in a somewhat unpredictable manner.Thiswas explained by the interaction between the supports and the damaged regions at the corners,which ultimately modified the stresses along the pillar periphery.The amount of displacement reduction obtained by increasing the support density illustrates the potential of BBMto be used as a support design tool.
基金supported by National Natural Science foundation of China(Nos.21374060 and 21574081)
文摘Chiral supramolecules prepared by the additive-driven self-assembly of block copolymers provide a facile method to construct helical nanostructures. In this study, we investigated the chiral transfer from chiral tartaric acid to poly（styrene）-b-poly（ethylene oxide） using small-angle X-ray scattering,transmission electron microscopy, circular dichroism, and vibrational circular dichroism. The results showed that the chirality was transferred to both the segments of block copolymer irrespective of the interaction with the chiral additives and formation of helical phase structure. However, the chirality transfer was carried out using different methods： for poly（ethylene oxide） segments, the chirality transfer was carried out via direct hydrogen bond formation; for polystyrene segments, the chirality transfer was carried out via the cooperative motion of block copolymers during the thermal annealing.
