To explore the crack propagation and failure process of surrounding rock with deep cracks under external stress adjustment, the failure of cracked specimens under external load was studied. The required test pieces were prepared by using a self-developed mold and using cement mortar as a similar material. Through the uniaxial compression test, the basic mechanical properties of the material and the specimen were obtained, and the crack propagation process and the failure evolution mechanism of the specimen under different crack inclination angles and loading rates were revealed. The test results show that the presence of cracks can significantly affect the overall strength of the specimen, and the strength and failure mechanism of the specimen vary with the change in the crack angle and rate of loading. The larger the crack inclination angle, the lower the strength of the specimen, and the two are linearly related. With the increase in the loading rate, the failure mode of the specimen gradually changes, the dynamic effect is enhanced, and typical characteristics of a rockburst appear. Furthermore, the reasons for the modes of failure and changes in strength of the specimens were analyzed from the energy point of view, and the non-contact full-field strain measurement system (DIC) was used to explain the macroscopic failure modes of the specimens from a meso-level perspective. Combining this with the failure behavior of the specimen, reasonable suggestions are proposed for the smooth construction of the actual project in the later stage.

In this experimental study, a Servo-hydraulic Universal rock mechanics testing machine (Serial Number: 1606008) was used to maintain the consistency of the loading method and reduce error. According to the measured data, the failure law of the cracked specimen was analyzed by Origin 2018 drawing.