摘要
为确保川西高原大型露天采场高陡板岩质边坡的稳定性,有必要对不同介质中冻融循环作用下高寒地区板岩劣化损伤特性的发展规律展开研究.将板岩分别置于空气和水中进行冻融试验,在达到相应循环次数后测定试样质量、饱和含水率和纵波波速,进行单轴抗压强度测试,并观察岩样宏观形貌,综合分析其在冻融作用下相关力学特性的劣化规律.结果表明:冻融作用下板岩各力学参数表现出明显的劣化效应,随着暴露在冻融环境中时间的增长,试样质量损失速率、吸水速率波动上升,纵波波速、单轴抗压强度和弹性模量呈下降趋势,饱和含水率曲线呈负指数增大;岩样因温度变化自身产生的胀缩、内部黏土矿物吸水聚集膨胀是板岩破坏的主要原因;随着冻融循环次数的增加,试样劣化速率减缓,最后趋于稳定;水分是板岩劣化的重要因素,相同冻融循环次数下,水中进行冻融循环的岩样劣化程度更大,劣化速度更快.
Abstract
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.
维普
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