Study on degradation of mechanical and apparent properties of slate under freeze-thaw cycles
In order to ensure the stability of high steep slate slope in large open-pit stope in western Sichuan Pla-teau,it is necessary to study the development law of the deterioration and damage characteristics of slate in the high cold area under the action of freeze-thaw cycles in different media,this paper selected the typical slate of the slope of Sichuan Jiajika spodumene mine as the research object,and divided slate into two groups,which were respectively placed in air and water for freeze-thaw cycle tests. The mass,saturated water content,longitu-dinal wave velocity and stress-strain curve of slate samples were tested after different freeze-thaw cycles;in or-der to study the deterioration damage mechanism of slate samples under the alternating action of freeze-thaw,the apparent morphology of slate patterns after freeze-thaw test was observed,and the deterioration response degree of each damage factor under the action of freeze-thaw cycle was comprehensively analyzed. The results show that:Physical and mechanical parameters of slate,such as mass,saturated water content,longitudinal wave ve-locity,compressive strength and elastic modulus,show obvious deterioration response during the freeze-thaw cy-cle,as the number of freeze-thawing increases,the mass loss rate and water absorption rate of the sample fluctu-ate up,the longitudinal wave velocity,uniaxial compressive strength and elastic modulus decreased,and the sat-uration moisture content curve showed negative exponential growth;under the alternating action of freezing and thawing,the expansion and contraction of rock samples due to temperature change,and the internal clay miner-als absorb water and accumulate and expand,are the main reasons for the failure of slate;with the increase of freezing and thawing times,the deterioration rate of the slate gradually slows down and finally becomes stable;water is an important factor in the deterioration of slate,under the same number of freeze-thaw cycles,the deteri-oration degree and speed of slates undergoing freeze-thaw cycles in water are greater.
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