ABSTRACT
ABSTRACT: Gypsum pillars left in the gob area of gypsum mines are subject to the physical and chemical actions of water, which degrades their mechanical properties and eventually leads to gob collapse. To investigate the effect of water content on the stability of gypsum pillars, laboratory tests were conducted on gypsum specimens collected from a gypsum mine in Changde. Meanwhile, the tributary area method and the equation of pillar strength proposed by Bieniawski were applied to analyze the stability of gypsum pillars with different water contents based on the test results, and the safe depth of mining under different moisture conditions was determined. The experimental results indicated that the uniaxial compressive strength and elastic modulus of gypsum specimen decreased with increasing water content. The calculated results indicated that, at the same depth, the stability of gypsum pillars decreased with the increase in water content.
