定向热冲击花岗岩体内部温度场分布及其演化特征研究

Study on the Distribution and Evolution Characteristics of Temperature Field in Granite Under Directional Thermal Shock

为了探究热力定向破断煤层坚硬顶板新型方法的可行性,利用自主研制的定向热传导温度控制系统,研究了高温热源作用下花岗岩定向热冲击破裂效果,揭示了岩石不均匀受热情况下温度演化规律及其与破裂的内在联系。结果表明:不同位置升温速率随时间变化呈现先升高后降低的趋势,花岗岩试样的破坏并非于升温速率到达峰值时产生,花岗岩的破坏是热冲击效应及高温对岩石性质的弱化综合作用下的结果;随着热冲击温度的升高,非加热向测点的升温速率有很大程度的上升,对定向热冲击破岩存在一定的不利影响;在更高温度的热源作用下,花岗岩破裂时间缩短,在试验条件下热冲击温度与破裂时间的关系可用Allometricl模型进行有效拟合。研究结果可为热力定向破断坚硬岩石新型破岩方法的深入研究提供理论参考依据。

In order to explore the feasibility of the new method of thermal directional breaking the hard roof of coal seam,the directional thermal shock fracture effect of granite under the action of high temperature heat source was studied by using the self-developed directional thermal conduction temperature control system,and the temperature evolution law of rock under uneven heating and its internal relationship with fracture were revealed.The results show that the heating rate at different positions increases first and then decreases with time.The failure of granite samples does not occur when the heating rate reaches the peak value.The failure of granite is the result of the combined effect of thermal shock effect and the weakening of rock properties by high temperature.With the increase of thermal shock temperature,the heating rate of non-heating to the measuring point increases greatly,which has a certain adverse effect on directional thermal shock rock breaking.Under the action of high temperature heat source,the fracture time of granite is shortened.Under the experimental conditions,the relationship between thermal shock temperature and fracture time can be effectively fitted by Allometricl model.The research results can provide a theoretical reference for the in-depth study of the new rock breaking method of thermal directional breaking hardrock.