Fatigue properties analysis of cracked rock based on fracture evolution process

Abstract

Fracture evolution process (initiation, propagation and coalescence) of cracked rock was observed and the force− displacement curves of cracked rock were measured under uniaxial cyclic loading. The tested specimens made of sandstone-like modeling material contained three pre-existing intermittent cracks with different geometrical distributions. The experimental results indicate that the fatigue deformation limit corresponding to the maximal cyclic load is equal to that of post-peak locus of static complete force−displacement curve; the fatigue deformation process can be divided into three stages: initial deformation, constant deformation rate and accelerative deformation; the time of fracture initiation, propagation and coalescence corresponds to the change of irreversible deformation.

Cyclic and Fatigue Behaviour of Rock Materials: Review, Interpretation and Research Perspectives

“…Several studies point out that monotonic stress-strain curves act as a failure locus for cyclically loaded samples (Haimson and Kim 1971;Martin and Chandler 1994;Yamashita et al 1999;Zhang et al 2008;Xiao et al 2009;Guo et al 2012;Song et al 2013;Liu et al 2017). An example of such a phenomenon is reproduced in Fig.…”

Hydraulic Fracturing of the Floridan Aquifer from Aquifer Storage and Recovery Operations

“…For the three primary methods, a factor of safety (FS) of 10 percent was applied to the predictive hydraulically induced fracturing results to account for assumptions applied to the evaluations and to define ASR design and operational waterpressure thresholds above which caution should be exercised. Fracturing the Floridan Aquifer Several other factors may influence FAS rock matrix stability, rendering it more or less susceptible to hydraulically induced fracturing due to installation of a well borehole or ASR operational recharge and recovery phases; these include: (1) resultant stress intensity on the well borehole wall due to decreasing water pressure in the well (Aadnoy, 1996), (2) magnitude redistribution of the pre-drilling in situ principal stress field around the well borehole (Fjar et al, 2008), (3) chemical dissolution or precipitation of FAS rock matrix, and (4) fatigue failure of the well borehole wall due to cyclic ASR operations (Haimson, 1978;Higdon et al, 1985;Singh, 1989;Alehossein and Boland, 2004;and Zhang et al, 2008). The effects, whether positive or negative, of these four factors on the initiation of hydraulically induced fracturing will likely be very minimal and confined to the rock matrix at and very near the well borehole wall and are considered minor limitations of the methodology.…”

Compressive failure model for brittle rocks by shear faulting and its evolution of strength components

“…Furthermore, the formation of tensile cracks within the shear bands suggests that tensile fracture is probably a percussive mechanism of the loss of cohesion at the tip of the shear band [22]. The interaction and coalescence of branch cracks promote the breakage of rock bridges further making the stress drop sharp [19,23,24], and after that the frictional resistance mobilises along the newly created plane. Therefore, the micromechanical failure process in a localised zone can be divided into two stages: the brittle breakage stage (bond rupture of rock bridge) and the sliding stage (frictional resistance of failure plane mobilisation).…”