Effect of confining pressure strength on the characteristics of energy evolution and fatigue fracture of the coal‐rock structural body

Abstract

The stability of coal seam‐overlying strata is significant to the safety of coal mines. The coal‐rock height ratio and confining pressure strength affect the stability of coal seam‐overlying strata. The research purpose of this paper is to obtain the effects of confining pressure and coal‐rock height ratio on the mechanical properties, energy evolution characteristics, and damage variables of structural body through the uniaxial loading, uniaxial cyclic loading, and triaxial cyclic loading experiment. Based on the evolution characteristics of the energy, the concept of energy dissipation ratio is put forward, and the effect of height ratio and confining strength on the energy dissipation ratio are compared and analyzed. The research results of this paper can provide theoretical reference for exploring the stress and energy evolution of coal seam‐overlying strata during chamber excavation and working face mining.

Mechanical Behaviors and Precursory Characteristics of Coal-Burst in Deep Coal Mining for Safety-Sustainable Operations: Insights from Experimental Analysis

“…Their findings indicated that higher confining pressures resulted in the accumulation of more elastic strain energy in the coal prior to failure. Li et al [11] proposed the concept of an energy dissipation ratio to examine the influence of confining pressure on the mechanical properties and damage evolution of rock structures using triaxial cyclic load experiments. Du et al discovered that the ultimate strength and residual strength of coal samples exhibited a linear increase with confining pressure, and that confining pressure could impede crack expansion while enhancing the energy storage capacity of coal [12].…”