Acoustic Emission Characteristics of Compressive Deformation and Failure of Siltstone under Different Water Contents

Abstract

The uniaxial compression and acoustic emission (AE) monitoring of siltstone specimens in the Gongchangling open-pit iron mine in Liaoning Province was conducted by evaluating the effects of three water saturation levels: dry, natural, and water-saturated. The siltstone AE characteristics were analyzed according to water content; the relationship between the AE characteristics and the growth and expansion of siltstone cracks was subsequently discussed. Research results indicated the following: siltstone specimens had distinctly different mechanical properties and AE characteristics according to water content; as the water content increased the compressive strength and elasticity modulus of specimens decreased. In the compacting phase of specimens under compression, the AE count rate of the water-saturated specimen was relatively small and the events were relatively stable. In the linear-elastic deformation phase, the AE count rate of the dry specimen increased sharply, reaching approximately 400 times/s. In the plastic yield deformation phase, the peak value of the AE count rate of the dry specimen ranged between 955 and 1,068 times/s, whereas that of the water-saturated specimen only attained a range of 635 to 782 times/s. In the failure phase, the time to reach the peak stress value of the dry specimen was increased as compared to that of the AE count rate.

Experimental Study of Confined-Pressure Soaking on Sandstone Damage-Fracture Characteristics Using Acoustic Emission and Energy Dissipation

“…The loading specimen fracture is the combined action of the internal micro-crack closure, energy accumulation, transformation and release [37,38]. AE monitoring system could receive the signal of a damage-failure process for loading specimen, reflecting the crack propagation [39,40]. The CPS modification would inevitably lead to the change of fracture characteristics.…”

Mechanical Properties and Acoustic Emission Characteristics of Karst Limestone under Uniaxial Compression

“…ese cause the promoting plastic behaviour and the dissipation of internal energy. From the macroscopic view, the strength and AE activity will decrease [41][42][43].…”