Experimental study of strength characteristics of coal specimens after water intrusion

摘要

We carried out uniaxial compressive experiments on coal specimens with different moisture contents to gain a better understanding of the water-induced weakening characteristics of coal. The effects of moisture content on the strength and deformation characteristics of the specimens were analyzed. The results of the uniaxial compressive experiment demonstrate that the full stress-strain curve presents plastic deformation characteristics with the increase of the moisture content in the coal specimens. A positive linear relation between the peak strain and moisture content and a negative one between the compressive strength and moisture content were observed. The results also show that the elastic modulus and the moisture content satisfy a negative exponential function. Taking the obtained relation as boundary conditions and applying the statistical damage theory and strain equivalence hypothesis, we derived a statistical constitutive damage model for coal which can reflect the effects of the moisture content.