Dynamic failure analysis and support optimization for web pillars under static and dynamic loading using catastrophe theory

Abstract

Web pillars enduring complex coupled loads are critical for stability in high-wall mining. This study develops a dynamic failure criterion for web pillars under non-uniform loading using catastrophe theory. Through the analysis of the web pillar-overburden system’s dynamic stress and deformation, a total potential energy function and dynamic failure criterion were established for web pillars. An optimizing method for web pillar parameters was developed in highwall mining. The dynamic criterion established was used to evaluate the dynamic failure and stability of web pillars under static and dynamic loading. Key findings reveal that vertical displacements exhibit exponential-trigonometric variation under static loads and multi-variable power-law behavior under dynamic blasting. Instability risks arise when the roof’s tensile strength-to-stress ratio drops below 1. Using catastrophe theory, the bifurcation set Δ<0 signals sudden instability. The criterion defines failure as when the unstable web pillar section length l₁ exceeds the roof’s critical collapse distance l₂. Case studies and simulations determine an optimal web pillar width of 4.6 m. This research enhances safety and resource recovery, providing a theoretical framework for advancing highwall mining technology.

Keywords

Non-uniform loading / Highwall mining / Web pillar / Dynamic failure criterion / Parameter optimization design

Acknowledgement

This work was supported by the National Natural Science Foun-dation of China (Nos. 52204136, 52474100, and 52204092).

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