Numerical simulation of the influence of pillar strength on the internal synergy relationship in the backfill‐pillar system

Abstract

The influence of the strength of the pillar on the bearing characteristics of the backfill‐pillar system (BPS) based on the mechanism of backfill. Quantitative synergy relationships between backfill and pillar were defined and pointed out. There are four kinds of quantitative synergy relationships in the bearing process of the system. To verify the relationship, systems with different strengths of the pillar were selected to carry out numerical simulation experiments, and a mathematical calculation method to quantify synergy relationship in the BPS was designed. The results show that the system under the low strength of the pillar presents the overall increase in bearing characteristics, while the system under the high strength of the pillar presents “N”‐type bearing features. Four kinds of quantitative synergy relationships able to characterise the action mechanism between backfill and pillar in each stage of the bearing of the system. Through analysis and discussion, it was concluded that the essential reason for the difference in bearing characteristics is that the effect of displacement restraint, joint support, and passive compressive weaken with the increase of the strength of pillar. The effect of pillar strength on the internal synergy of BPS is well verified by numerical simulation test.