Discontinuities are an inherent part of the rock mass and majorly affect the stability of the excavation skin and pillars.The dip of the discontinuities and their properties also have a significant effect on the stren...Discontinuities are an inherent part of the rock mass and majorly affect the stability of the excavation skin and pillars.The dip of the discontinuities and their properties also have a significant effect on the strength of the pillars.Empirical approaches are commonly used to determine the pillar strength but can overestimate the strength and don’t consider the inclination of the pillars and the strength reduction caused by discontinuities.Numerical modeling is a powerful tool and if calibrated can be used to evaluate the strength of the pillars with discontinuities having a range of properties.The effect of a discontinuity on inclined pillars was conducted which has been seldom considered in evaluating the pillar strength.Three-dimensional vertical pillars were simulated,and the pillar strength was calibrated to accepted theoretical results and then the discontinuities were introduced in different pillar inclinations with distinct width to height ratios to gain an insight into the effective pillar strength reduction.Based upon the results,it was found that the discontinuities have a significant effect with the increase in the inclination of the pillars even at a higher width to height ratios.展开更多
Pillar stability is one of important aspects for underground mines.Generally,the stability of the pillars is evaluated empirically based on case studies and site-specific rock mass conditions in mines.Nevertheless the...Pillar stability is one of important aspects for underground mines.Generally,the stability of the pillars is evaluated empirically based on case studies and site-specific rock mass conditions in mines.Nevertheless the empirical approach applicability can sometimes be constrained.The numerical-based approaches are potentially more useful as parametric studies can be undertaken and,if calibrated,can be more representative.Both empirical and numerical approaches are dependent on the strength evaluation of the pillars while the strain developing in the pillars is seldom taken into consideration.In this paper,gypsum and sandstone samples were tested in laboratory with different width-to-height ratios (W/H) to adapt the strain evaluation method to the laboratory-based pillars.A correlation was then developed between the strain and the width-to-height ratio for pillar monitoring purposes.Based on the results,a flowchart was created to conduct back analysis for the existing pillars to evaluate their stability and design new pillars,considering the strain analysis of the existing pillars with the W/H ratios modelled.展开更多
文摘Discontinuities are an inherent part of the rock mass and majorly affect the stability of the excavation skin and pillars.The dip of the discontinuities and their properties also have a significant effect on the strength of the pillars.Empirical approaches are commonly used to determine the pillar strength but can overestimate the strength and don’t consider the inclination of the pillars and the strength reduction caused by discontinuities.Numerical modeling is a powerful tool and if calibrated can be used to evaluate the strength of the pillars with discontinuities having a range of properties.The effect of a discontinuity on inclined pillars was conducted which has been seldom considered in evaluating the pillar strength.Three-dimensional vertical pillars were simulated,and the pillar strength was calibrated to accepted theoretical results and then the discontinuities were introduced in different pillar inclinations with distinct width to height ratios to gain an insight into the effective pillar strength reduction.Based upon the results,it was found that the discontinuities have a significant effect with the increase in the inclination of the pillars even at a higher width to height ratios.
文摘Pillar stability is one of important aspects for underground mines.Generally,the stability of the pillars is evaluated empirically based on case studies and site-specific rock mass conditions in mines.Nevertheless the empirical approach applicability can sometimes be constrained.The numerical-based approaches are potentially more useful as parametric studies can be undertaken and,if calibrated,can be more representative.Both empirical and numerical approaches are dependent on the strength evaluation of the pillars while the strain developing in the pillars is seldom taken into consideration.In this paper,gypsum and sandstone samples were tested in laboratory with different width-to-height ratios (W/H) to adapt the strain evaluation method to the laboratory-based pillars.A correlation was then developed between the strain and the width-to-height ratio for pillar monitoring purposes.Based on the results,a flowchart was created to conduct back analysis for the existing pillars to evaluate their stability and design new pillars,considering the strain analysis of the existing pillars with the W/H ratios modelled.
