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

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

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。

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.