When highwall mining technology is applied to recover large amounts of residual coal left under the highwall of a big open-pit mine, a reasonable coal pillar width is required to ensure the stability of the web pillars. Using numerical simulations, this paper studied the characteristics of the abutment stress distribution in the web pillars under different slope angles and mining depths, and established a relation describing the stress distribution in the web pillar. The relationship between the abutment stress and the ultimate strength of the web pillar under different pillar widths was also analyzed. In combination with the failure characteristics of the pillar yield zone, this relationship was used to explore the instability mechanism of web pillars. Finally, the optimal retaining widths of the web pillars were determined. Based on the modeling results, a mechanical bearing model of the web pillar was established and a cusp catastrophe model of pillar-overburden was constructed. Additionally, the web pillar instability criterion was derived. By analyzing the ultimate strength of the web pillars, a formula for calculating the yield zone width either side of the pillars was established. Using the instability criterion of web pillars in highwall mining, a reasonable pillar width can be deduced theoretically, providing significant guidance on the application of highwall mining technology.

大型露天煤矿高壁开采技术在采收大量剩余煤时，需要合理的煤柱宽度来保证腹柱的稳定性。采用数值模拟方法，研究了不同坡角和采深下腹板柱内应力分布特征，建立了描述腹板柱内应力分布的关系式。分析了不同柱宽下腹板柱的支座应力与极限强度的关系。结合支柱屈服区的破坏特征，利用该关系式探索腹板支柱失稳机理。最后，确定了网柱的最佳保持宽度。根据建模结果，建立了腹板柱的力学承载模型，构建了柱上覆岩尖突变模型。此外，还导出了网柱不稳定性判据。通过分析网柱的极限强度，建立了柱子两侧屈服区宽度的计算公式。利用高壁开采腹柱失稳判据，可以从理论上推导出合理的柱宽，为高壁开采技术的应用提供重要指导。建立了计算柱子两侧屈服区宽度的公式。利用高壁开采腹柱失稳判据，可以从理论上推导出合理的柱宽，为高壁开采技术的应用提供重要指导。建立了计算柱子两侧屈服区宽度的公式。利用高壁开采腹柱失稳判据，可以从理论上推导出合理的柱宽，为高壁开采技术的应用提供重要指导。