Study on the Failure Characteristics of Frozen Soil After Freeze-Thaw Cycle on Thick Coal Seam in High Cold Area
In order to reveal the failure characteristics of frozen soil after freeze-thaw cycle on thick coal seam in high-altitude and cold region,taking the frozen soil body on the thick coal seam in high cold area as the research object,electro-hydraulic servo rock uniaxial experimental machine was used to carry out the rock mechanics experiments.The influence characteristics of freeze-thaw cycles on the structure,peak strength,elastic modulus,and crack development of frozen soil body were obtained by a non-metallic ultrasonic detector to test the wave velocity of artificial specimens with different water contents.It is concluded that under a certain water content condition,as the number of freeze-thaw cycles increases,the fitting function curves of the peak strength and freeze-thaw cycle number,as well as the elastic modulus and freeze-thaw cycle number of artificially frozen soil specimens are both parabolas with an opening downward.The decrease in elastic modulus and peak strength depends on the rate of strain accumulation and damage development.As the number of freeze-thaw cycles increases,the wave velocity of artificially frozen soil specimens gradually decreases,indicating good development of internal pores and cracks.From the perspective of micromechanics,after several freeze-thaw cycles,the permeability coefficient of frozen soil gradually increases,the speed of water migration accelerates,and the effect of frost heave force is obvious.Fine grained soil is gradually compacted,while a large number of new-born micro cracks are generated,and the porosity gradually increases.
Freeze-thaw cycleThick coal seamFrozen soil bodyPorosityFrost heave force
万方数据
维普
