Mechanical Properties and Acoustic Emission Characteristics of Weakly Cemented Sandstone With Different Grain Sizes

Abstract

The weakly cemented sandstone is widely distributed in the Western Mining Area, which is mainly formed by mineral grains and cemented minerals through compaction and cementation. To study the influence of grain size on the mechanical properties and acoustic emission (AE) characteristics of weakly cemented sandstone, uniaxial compression and Brazilian splitting AE tests were carried out on four weakly cemented sandstone specimens with different grain sizes. The physical properties, mechanical behaviors, and AE characteristics of sandstone under two conditions were analyzed, and the microfailure mechanism was investigated. The results show that the P-wave velocity, density, uniaxial compressive strength (UCS), and tensile strength of weakly cemented sandstones with different grain sizes decrease with the increase of grain size. The medium sandstone and coarse sandstone exhibit ductile failure, while the siltstone and fine sandstone exhibit brittle failure under the two conditions. The distribution of AE signal strength is nearly Gaussian in the time domain. The peak frequency and upper limit of signal strength are negatively correlated with grain size, and the occurrences of lots of high-strength AE signals can be used as the precursor of sandstone failure. The damage evolution shows the trend of low-speed damage-accelerated damage-low-speed damage, and the damage increase at the peak load is negatively related to the grain size. The microfailure mechanism is the tension-shear mixed failure, which is dominated by tensile failure, with few shear failures. The proportion of shear cracks is positively correlated with the grain size under uniaxial compression, while there is no significant correlation between shear cracks and grain size under Brazilian splitting.

Study on Staged Damage Behaviors of Rock-like Materials with Different Brittleness Degrees Based on Multiple Parameters

“…In general, AE events associated with tensile failure have lower RA and higher AF values. Meanwhile, AE events associated with shear failure have higher RA and lower AF values [ 29 , 30 , 31 , 32 ].…”

“…The rock fracture damage process has been described using the ringing count, event number, and energy parameters of AE data [ 26 , 27 , 28 ]. Rising time/amplitude (RA) and average frequency (AF) are frequently used to analyze qualitative aspects of rock fracture mechanisms [ 29 , 30 , 31 , 32 ]. Earthquake theory b value analyses have also become important in rock AE characteristic research.…”

Failure characteristic and acoustic emission spatio‐temporal evolution of coal under different cyclic loading rates

“…Wang et al 26 identified the failure points of limestone using the tangent damage factor (TDF) based on the AE signals. The deformation behaviors and AE evolution of weakly cemented sandstone from Shendong Coalfield were analyzed 27–29 . Liu et al 30 studied the effect of loading rate on tensile properties and multiparameter characteristics of coal.…”

“…The deformation behaviors and AE evolution of weakly cemented sandstone from Shendong Coalfield were analyzed. [27][28][29] Liu et al 30 studied the effect of loading rate on tensile properties and multiparameter characteristics of coal. Dou et al 31 investigated the mechanical behavior and AE evolution of sandstone with various inclined precracks.…”

An experimental study of the correlation between P-wave velocity and the physical properties of weakly cemented formations

“…Many scholars have conducted studies in this area. Bin et al 5 argued that the P-wave velocity of weakly cemented sandstone with different particle sizes decreases with increasing particle size. Tutuncu et al 6 made weakly cemented sandstone using quartz as particles and studied the effect of permeability on elastic wave velocity.…”