加载速率对不同温度状态石灰岩力学性能影响的试验研究

借助美国MTS810电液伺服材料试验机和高温炉,对常温和600℃两种温度状态下石灰岩试件进行不同加载速率下的单轴压缩试验,得到石灰岩力学性能随加载速率的变化规律。结果表明:常温时,石灰岩岩样在3×10-4~3×10-3 mm/s的低应变率范围内,加载速率对峰值应力和弹性模量影响不大,在加载速率为3×10-3~3×10-1 mm/s的区段内,峰值应力和弹性模量均呈明显上升趋势;600℃时,峰值应力和弹性模量随加载速率增加变化不大。常温时,不同加载速率下石灰岩岩样均为竖向劈裂破坏,且在3×10-3~3×10-1 mm/s的加载速率区段中,随加载速率的增加,劈裂面逐渐增多;600℃时,石灰岩岩样在不同加载速率下均为剪切破坏。

Effect of loading rate on mechanical properties of limestone at different temperatures

The uniaxial compression tests for limestone specimens were carried out at different loading rates at room temperature and 600 ℃ using the Rock Mechanics Servo-controlled Testing System MTS810 and high temperature furnace.The mechanical properties of limestone at varing loading rates were studied.The results show that,the peak strength and elastic modulus of lime-stone changed little at low loading rates from 3×10-4 mm/s to 3×10-3 mm/s,but an increasing trend occurred when loading rate changed from 3×10-3 mm/s to 3×10-1 mm/s at room temperature;the peak strength and elastic modulus changed little with the increase of loading rate at 600 ℃.The failure mode is vertical splitting failure at different loading rates at room tempera-ture,cleavage planes increased gradually as the loading rate changed from 3×10-3 mm/s to 3×10-1 mm/s;at 600 ℃,the failure mode is shear failure at different loading rates.