超高温条件下花岗岩力学性质演化规律模拟研究

Numerical Study on Evolution Law of the Mechanical Properties of Granite under Ultra-High Temperature Conditions

为提高深层干热岩破碎效率,以干热岩地层常见岩性-花岗岩为研究对象,提出超高温条件下花岗岩力学性质演化规律研究。鉴于室内实验方法的局限性,主要采用数值模拟和理论计算等研究方法,建立了高温花岗岩巴西圆盘劈裂数值模型,探究了硬质花岗岩在温度-压力联合作用下岩石应力场分布特征与扰动机制。研究发现:在单轴径向压缩载荷下,高温花岗岩各向应力分布受到显著扰动,岩石沿横轴拉伸应力、两端载荷施加位置附近压缩应力和剪切应力均显著减小,导致裂纹越容易扩展。温度越高,岩石损伤越明显,其岩石抗拉强度越低。研究结果揭示了温度作用下花岗岩力学性质演化规律,可为深层干热岩资源的高效开发提供理论依据。

To improve the rock-breaking efficiency of deep dry hot rock, taking granite, a common lithology of dry hot rock formation, as the research object, the changes in the mechanical properties of granite under ultra-high temperature was proposed. In view of the limitations of laboratory experimental methods, the Brazilian disc splitting numerical model of high-temperature granite was established by using numerical simulation and theoretical calculation methods, and the distribution characteristics and disturbance mechanism of stress field of hard granite under temperature-pressure conditions were investigated. It is found that under uniaxial and radial compression load, the stress distributions of high-temperature granite get significantly disturbed, leading to lower tensile stress along the horizontal direction, smaller compression and shear effect near the loading points, and easier fracture conduction. The higher the temperature, the more obvious the rock damage and the lower the tensile strength of the rock. The results reveal the evolution law of mechanical properties of granite under the effect of temperature, which can provide theoretical basis for efficient development of deep dry hot rock resources.