Study on the Law of Failure Acoustic-Thermal Signal of Weakly Cemented Fractured Rock with Different Dip Angles

The diagenetic environment and geological conditions in the west are special, and weakly cemented rocks with low strength, poor cementation and well-developed fissures are widely distributed in coal measure strata. Considering the changes of acoustic emission and thermal infrared signals in the process of rock fracture, it is of great significance to study the characteristics of acoustic-thermal signals in the failure process of weakly cemented fractured rocks for expanding the analysis methods of rock fracture laws. In order to study the evolution law of acoustic-thermal signal in the failure process of weakly cemented fractured rocks with different dip angles, biaxial compression tests were carried out on the weakly cemented sandstone samples of Hongqingliang coal mine. Monitoring was carried out, and a joint analysis index of acoustic-thermal sensitivity was proposed. The research results show that the time series sensitivity of the combined acoustic-thermal index is in the order of medium-dip fractured rocks (30-60 degrees) > small-dip fractured rocks (0-30 degrees) > high-dip fractured rocks (60-90 degrees); The peak sensitivity of the joint index is in the order of high-dip fractured rocks (60-90 degrees) > medium-dip fractured rocks (30-60 degrees) > small-dip fractured rocks (0-30 degrees); The thermal infrared temperature signal is earlier than the acoustic emission signal, and the joint index can reduce the hysteresis of acoustic emission signal and the spatial limitation of thermal infrared. The above research can provide a useful reference for solving the large deformation of the surrounding rock of the roadway in the weakly cemented coal measure stratum and ensuring the long-term stability of the rock mass engineering.

Automated summary

Studying the characteristics of acoustic-thermal signals in the failure process of weakly cemented fractured rocks is of great significance for expanding the analysis methods of rock fracture laws. Biaxial compression tests were conducted on weakly cemented sandstone samples to investigate the evolution law of acoustic-thermal signals. The joint analysis index of acoustic-thermal sensitivity was proposed and the research results showed different sensitivities and sequences of the joint index for fractured rocks with different dip angles.