Phenomenon of the Emission of Microparticles under Quasi-Static Loading of Rocks

摘要

The article presents the results of experimental studies on the phenomenon of microparticle emission from the free surface of rock samples with a throughhole under uniaxial compression as a stress concentrator. The technique of experimental studies with the use of laser spectroscopy of particle sizes in the air has been developed. As a result of experimental studies the formation of microparticles and their detachment from the free surface at a certain level of stresses were documented The phenomenon of microparticle emission is observed in samples of rocks with different physical and mechanical properties (dolomite, granite, limestone, and samples of concrete). Quantitative estimates were made of the emission of sub-micron particles in the range of 0.3～5. 0 microns, depending on the operating voltage. Disperse composition of the particles, the dynamics of their formation depend on the petrographic characteristics of rocks, their degree of tension, and loading parameters. The quantity of particles generated during the testing of samples representing one type of rock in some cases differs significantly. This is explained by varying degrees of microfracturing of the samples, which presence predetermines the course of deformation and disintegration of the samples. In the emission of particles there is a mode of exacerbation-a dramatic increase of emission intensity, which precedes the disintegration of the sample. In rock disintegration control the dramatic enhancement of particle emission can serve an indicator of the forthcoming macrodisintegration. The research results suggest a conclusion that one of the mechanisms of sub-micron particle formation in the course of disintegration can be explained by the surface detachment of microscopic fragments. The established patterns and dependences have served a basis for the development of a radically new instrumental method for predicting men-induced phenomena resulting from the uncontrolled disintegration of the rock mass. A method has been development for the registration of fine particles with a laser aerosol spectrometer during the deformation and disintegration of rocks.