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以石灰岩为研究对象,对其在高温作用下的热膨胀特性进行了试验研究。为弄清产生热膨胀的原因,对高温后石灰岩试件的孔隙率、超声波速和元素组成进行了试验研究。试验结果表明,高温作用下石灰岩将发生热膨胀,热膨胀量与试验时间的关系曲线可分为4个阶段,热膨胀量的大小与试验温度有关且为非线性关联;高温后石灰岩的孔隙率变化总体呈随温度升高而增加趋势,且以500℃为分界温度,分为缓慢增加和急剧增加2个阶段。而超声波速检测表明,高温后试件内超声波传播速度变化规律复杂,呈波浪形;高温后试件组成元素检测表明,试件内主要元素含量发生了较大变化;试件内孔隙、裂隙变化和组成、矿物成分分解是导致试件发生热膨胀的主要原因。
Taking limestone as the research object, the thermal expansion characteristics under high temperature were studied. In order to find out the cause of thermal expansion, the porosity, ultrasonic velocity and elemental composition of limestone samples after high temperature were studied. The results show that the thermal expansion of limestone will occur under the action of high temperature. The relation curve between thermal expansion and test time can be divided into four stages. The magnitude of thermal expansion is related to the test temperature and is nonlinear. The porosity of limestone after high temperature With increasing temperature and increasing trend, and to 500 ℃ as the demarcation temperature, divided into slowly increasing and rapidly increasing two stages. The ultrasonic testing showed that the ultrasonic propagation velocity in the specimen after the high temperature changed in a complicated and wavy pattern. The test of the elements in the specimen after the high temperature showed that the content of the major elements in the specimen changed greatly. The variation of porosity and fissure in the specimen And composition, the decomposition of mineral components is the main cause of thermal expansion of the specimen.