在一定应力状态下，热诱导产生的应力场和初始应力场相叠加，导致岩石中裂纹萌生，对岩石的力学性质造成影响。基于离散元方法，在不同初始应力状态下，对含有不同倾角预制裂纹模型的热裂过程进行研究。对相关热特征值进行分析，并根据Det.（σ_ij ）准则，结合第二不变量的演化过程，对热裂纹的扩展路径进行理论分析。结果表明：高应力状态下，热敏感性较强（起裂温度较低，裂纹扩展温度区间靠前，裂纹扩展剧烈），峰值温度较低，而峰值热应力较高；不同角度的预制裂纹也会影响相关热特征值，在同一初始应力状态下，随着预制裂纹角度的增加，热敏感性降低；热裂纹首先在预制裂纹尖端形成，随着温度的升高，应力第二不变量的分布发生改变，热裂纹在第二不变量最大处扩展。研究结果对深部热力破岩和岩石工程稳定性具有一定借鉴意义。

Under a certain stress state，the thermal induced stress field and the initial stress field are superimposed，resulting in the initiation of new thermal cracks on the basis of the original cracks，which affects the mechanical properties of the rock.However，the effect of thermal stress field can also be applied to rock crushing.It is necessary to study the fracture caused by thermal and mechanical action of rock.Due to the limited monitoring technology of the experiment under high temperature，the relevant research is difficult to carry out.Using the method of combining experiment and simulation，based on the experiment and the discrete element method，the cracking process caused by heat and force of prefabricated crack model with different inclination angles was studied under different initial stress states. The relevant thermal eigenvalues were analyzed，and the propagation path of thermal crack was theoretically analyzed according to the D e t . ( {\sigma }_{ij} ) fracture criterion and the evolution process of the second invariant in the heating process.The results show that under the high stress state，the thermal sensitivity is strong （the crack initiation temperature is low，the crack propagation temperature range is in the front，and the crack propagation process is intense），the peak temperature is low，but the peak thermal stress is high.Prefabricated cracks with different angles will also affect the relevant thermal eigenvalues. Under the same initial stress state，with the increase of prefabricated crack angle，the thermal sensitivity de-creases.Moreover，the peak temperature has a similar law.When the crack initiation state is reached，the thermal crack first forms at the tip of the prefabricated crack.With the increase of temperature，the distribution of the second invariant of stress changes，and the thermal crack will expand at the maximum of the second invariant.The research results have certain reference significance for deep thermal rock breaking and rock engineering stability.

http://www.goldsci.ac.cn/article/2022/1005-2518/1005-2518-2022-30-4-559.shtml