加热条件下煤岩力学行为与损伤演化特征研究

Study on Mechanical Behavior and Damage Evolution Characteristics of Coal and Rock under Heating Conditions

为研究地热循环地质条件对煤岩的力学行为及损伤发展的影响,开展不同温度下的煤岩循环加热单轴抗压强度试验。结果表明:不同温度下的煤岩在峰值应力点后均发生应力突降现象,煤岩应力-应变曲线均表现出明显的脆性破坏特征;随着温度的逐渐提高,煤岩的单轴抗压强度逐渐降低,二者之间呈线性关系;煤岩的弹性模量随温度升高呈现先升后降的变化趋势,这与高温作用下煤岩内部的水分含量的变化有关。

In order to study the influence of geothermal cycling geological conditions on the mechanical behavior and damage development of coal and rock, the uniaxial compressive strength tests of coal and rock under cyclic heating at different temperatures were carried out in laboratory. The results show that: the stress drop occurs suddenly after the peak stress point in coal and rock at different temperatures, and the stress-strain curves of coal and rock show obvious brittle failure characteristics;the uniaxial compressive strength of coal and rock decreases gradually with the increase of temperature, and there is a linear relationship between them;the elastic modulus of coal and rock increases first and then decreases with the increase of temperature. The change trend is related to the change of water content in coal and rock under the action of high temperature.