Experimental Study on the Mechanical Properties and Acoustic Emission Characteristics of Deep Soft Rocks under Low-Frequency Dynamic Disturbance

Abstract

The strong dynamic disturbance in deep mines seriously affects the safe and efficient mining of deep resources. In this study, we used the creep disturbance impact loading system and acoustic emission system to conduct experiments on soft siltstone specimens under a combination of dynamic and static loads. Based on the failure characteristics and waveform signals, the mechanical properties and acoustic emission characteristics of soft rocks under different dynamic disturbances were quantitatively revealed. The experimental results show that: (1) Under the dynamic disturbance, the deformation of the siltstone specimens increases as the initial average stress increases. When the axial stress exceeds the upper stress threshold, cracks continue to propagate, resulting in the destabilization of the specimen. (2) The magnitude of the initial average stress is closely related to the degree of damage and failure mode of the siltstone. With the increase in the initial average stress, the failure mode of the siltstone specimens gradually changes. As the initial average stress increases, the maximum load first decreases, then increases, and finally decreases, and the fitted curve is polynomial. We used the RFPA2D cyclic loading module to analyze the effect of the elastic modulus of each loading step on the damage evolution of the specimen under dynamic disturbance. The waveform characteristics during the evolution of the damage of the specimens were analyzed by extracting signals at the key points.

Special Issue on Experimental Investigation and Numerical Modeling of Rock Brittle Failure Behavior under High Stress Conditions

“…The dynamic and real-time development of microfractures can be monitored with acoustic emission technology and via seepage monitoring. Then, experiment research was conducted on soft siltstone specimens under a combination of dynamic and static loads by Dong et al [8]. The mechanical properties and acoustic emission characteristics of soft rocks were quantitatively revealed using a creep disturbance impact loading system and acoustic emission system.…”

Study on Characteristics of Failure and Energy Evolution of Different Moisture-Containing Soft Rocks under Cyclic Disturbance Loading

“…Malik et al [19] conducted dynamic compression experiments on basalt using a separated Hopkinson rod and proposed an empirical correlation of the dynamic increase factor of compressive strength. Dong et al [20] examined the mechanical properties of sandstone and found a nonlinear relationship between sample compressive strength and initial cyclic values. Arora et al [21] used sine wave loading to conduct cyclic compression tests on different types of rocks and concluded that the rock secant modulus degradation is related to the number of cycles and proposed a normalized relationship for rock modulus degradation.…”