The influence of the moisture on the physical and mechanical properties of the sandstone (Separate Unit “Kapitalna” coal mine”, Donbas)

Abstract

Purpose. The influence of the moisture on the physical and mechanical properties of rock is evaluated by the experimental research in the laboratory.Methodology. Laboratory studies of a coefficient of moisture capacity of the rock, determination of strain characteristics and strength, identification of the modulus of deformation and Poisson's ratio, statistical data processing based on correlationregres sion analysis.findings. According to the laboratory studies, the dependence diagrams of the normal stresses from deformations for dry and wet rock samples were obtained. The correlation of stress limit on compression, modulus of elasticity and the coefficient of lateral deformation from the moisture content of the rock were obtained. In the course of the experiment, on the average, differences of mechanical characteristics of dry and wet states of the sandstone were established: stress limit on compressive is decreased almost twice; the modulus of elasticity is reduced by 4 times; the coefficient of lateral deformation is increased by 2.3 times.originality. The empirical dependences of mechanical properties from gravimetric moisture capacity of the sandstone sample were determined on the basis of the experiments in the laboratory. The regression power function was obtained for stress limit and modulus of elasticity, and for the coefficient of lateral deformation it was logarithmic. The coefficient of lateral deformation at the time of the destruction of some wet samples exceeded theoretically acceptable value of 0.5.Practical value. Obtained results can be applied in mathematical or numerical modeling of stressstrain state of the rock given consideration to the importance of the study of the influence of moisture on physical and mechanical markers and properties of rocks. It is possible to control stressstrain state around the roadways using the methods and the means of dewatering or hydro saturation as to coal seams and rocks.