11.Hydrophysical properties of coal and the experimental researchof the weakening effect of immersion water

Abstract:

Through the hydrological experiments of determining porosity and permeability,the permeability of the coal body is0. 744 1 mD;the porosity is 2. 79% ~ 2. 83% ;through the design of uniaxial compression experiments of coal sample specimens underdifferent water content conditions,the attenuation law of mechanical parameters under different saturation conditions is quantitativelyanalyzed. Compared with the dry group,the peak strength of the halfsaturated group with 4. 25% water content decreased by 1. 77% ,the modulus of elasticity decreased by 15. 83% ,and the peak strain and Poisson＇s ratio increased by 17. 25% and 24. 00% ,respectively;for the halfsaturated group with 8. 25% water content,the peak strength decreased by 5. 73% ,the modulus of elasticity decreased by 30. 22% ,and the peak strain and Poisson＇s ratio increased by 35. 81% and 48. 00% . The results showed that water weakened the mechanical properties of coal samples significantly,the higher the degree of water immersion,the lower the values of peakstrength and elastic modulus,and the higher the values of peak strain and Poisson’s ratio.

Keywords: softening properties;weakening by water immersion;groundwater reservoir;hydrological experiment