Forecasting Catastrophic Rupture in Brittle Rocks Using Precursory AE Time Series

Abstract

An evidently precursory acoustic emission (AE) time series, characterized by a time‐reversed Omori law, is registered prior to the unconfined catastrophic rupture of brittle sandstone. This provides insights into the physical process controlling catastrophic rupture and underlies the failure forecast. The onset of acceleration of damage is first identified based on the acousto‐optical characteristics. The precursory time series of rise time (RT) rate is used to forecast pseudo‐prospectively the catastrophic rupture in the framework of the time‐reversed Omori law. Investigations on multiple unconfirmed failure cases on the laboratory scale show that forecasts become more precise and less biased as the precursory AE time series proceeds toward rupture. In contrast to retrospective forecast, pseudo‐prospective forecast obtains a higher quality. Moreover, the use of amplitude as a precursor benefits the increase of warning time, and the flaw‐to‐flaw interaction introduces a strong disturbance on the forecast.

Compression‐induced crack initiation and growth in flawed rocks: A review

“…Effectively monitoring and quantitatively identifying the precursors of the macrofracturing events in rocks are the key issues for the forecast of catastrophic rupture in rocks. 11,201 In the approach to the macrofracturing, the rock mass structure and other heterogeneous media are in the state of strain energy accumulation, which leads not only to the microcracking in rock matrix but also to the changes in electrical, thermoelectric, and piezoelectric properties of minerals in rocks. Accordingly, the acoustic, thermodynamic, electric, and magnetic precursors can be released from the rock mass.…”

“…For example, a 1-2 Â 10 3 -m 3 cliff collapse occurred in 2002 on the Normandie ocean shore, western France. 10,11 This cliff collapse was triggered by the rapid shear crack propagation from a pre-existing fault. Another example involved the step-path failure (resulted from the crack coalescence) in two gneiss slopes of the Xiaowan hydroelectric station, China.…”

Deformation and failure characteristics of sandstone subjected to true‐triaxial unloading: An experimental and numerical study

“…To date, the failure mode of brittle rock under various stress conditions has been extensively investigated by researchers. [52][53][54][55][56][57][58][59] Xu et al 19 also pointed out that under true-triaxial unloading conditions, the level of σ 1 at the unloading point had an influence on the transition of rock failure mode. However, few studies have been conducted to yield insights into the mechanism of macro fracture.…”

Experimental investigation of cracking behaviors of ductile and brittle rock-like materials

“…the cracking behaviors in rock or rock-like materials. Zhou et al [30] and Zhang et al [31][32][33][34] studied progressive failure of brittle rocks with non-isometric flaws. Such rock-like materials and real rock materials have not only common characteristics for crack evolution, but also differences caused by the material properties, loading methods, and specimen geometry [35][36].…”

“…Such rock-like materials and real rock materials have not only common characteristics for crack evolution, but also differences caused by the material properties, loading methods, and specimen geometry [35][36]. Moreover, since rock is a very complex and anisotropic material whose mechanical properties vary widely, ranging from hard rock with very high mechanical properties to soft rock with very low mechanical properties [30][31][32][33][34][35][36]. However, there is scarce study on the cracking behaviors and mechanical properties of ductile and brittle rock-like materials.…”