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对焦作石灰岩在常温及经历100℃～800℃不同温度作用后的物理力学特性进行了试验研究,详细分析了加温后石灰岩的表观形态、体积、质量、密度和纵横波波速以及单轴下石灰岩的峰值应力、峰值应变和弹性模量等的变化情况,并对石灰岩高温劣化的影响因素进行了分析。研究结果表明,高温使石灰岩的表观形态发生改变:在400℃以内,温度对石灰岩的物理力学性质的影响不大;200℃以下石灰岩的体积略微减少,超过200℃后石灰岩的体积明显增大,石灰岩的密度随温度的升高而逐步减少;随温度的升高,石灰岩的纵、横波波速大都呈现下降;高温后石灰岩的波速比变化呈无规律性;高温后石灰岩的动弹性模量随温度上升而下降。经历的温度超过400℃后石灰岩的峰值应力和弹性模量均有不同幅度的降低,而800℃内石灰岩的峰值应变随温度的升高变化不明显。温度引起的热应力作用、矿物组分和微结构变化导致石灰岩物理力学性质发生改变与高温劣化。
Focusing on the physical and mechanical properties of limestone at room temperature and under different temperatures from 100 ℃ to 800 ℃, the limestone’s apparent morphology, volume, mass, density and longitudinal and shear wave velocities after heating are analyzed in detail. Limestone peak stress, peak strain and elastic modulus and other changes, and the impact of high temperature limestone deterioration were analyzed. The results show that the high temperature causes the change of the apparent morphology of limestone: within 400 ℃, the temperature has little effect on the physical and mechanical properties of limestone; the volume of limestone decreases slightly below 200 ℃, and the volume of limestone increases obviously after 200 ℃ , The density of limestone gradually decreases with the increase of temperature. With the increase of temperature, most of the longitudinal and transverse wave velocities of limestone decrease. The variation of wave velocity ratio of limestone is irregular after high temperature. The dynamic elastic modulus Temperature rises and falls. After experiencing the temperature above 400 ℃, the peak stress and elastic modulus of limestone all decreased by different degrees, while the peak strain of limestone within 800 ℃ did not change obviously with the increase of temperature. Temperature-induced thermal stress, changes in mineral composition and microstructure lead to altered physical and mechanical properties of limestone and high temperature degradation.