Energy analysis for damage and catastrophic failure of rocks

Abstract

The development history and current state of studies on the characteristics and mechanisms of deformation and failure of rock materials were briefly reviewed from the viewpoint of energy. The main scope and the achievable objectives of the energy-based research system were expatiated. It was validated by experiments that the damage process of rocks can be well described by the rock damage evolution equation established based on energy dissipation. It was found from the uniaxial compression and biaxial compression tests that only a small proportion of the total input energy in hard rocks is dissipated before peak load and a large proportion in soft rocks is dissipated before peak load. For both hard and soft rocks, the energy dissipated after peak load accounts for a greater proportion. More energy would be required for rock failure under equal biaxial compression than under unequal biaxial compression. The total absorbed energy is different for rock failure under high-rate loading and low-rate loading. More fragmented failure pattern usually corresponds to higher energy absorption. The mesoscopic analysis on the damage and failure of bedded salt rocks showed that the energy dissipation is prominent and the total absorbed energy for rock failure is low when cracks propagate in the weak mud interlayer while it is contrary when cracks propagate in the salt rock. The energy accumulation, transfer, dissipation and release during the failure process of tunnel with impending failure under disturbance were analyzed theoretically based on the elastoplastic mechanics theory. Furthermore, the spatial distribution of energy dissipation and energy release of fractured rocks under unloading was simulated numerically. It was demonstrated that energy is likely to be released from the weakest surface under compression, which triggers the global failure of rocks.rock, deformation, failure, energy accumulation, energy dissipation, energy release Citation:Xie H P, Li L Y, Ju Y, et al. Energy analysis for damage and catastrophic failure of rocks.

Energy Evolution Characteristics and Distribution Laws of Rock Materials under Triaxial Cyclic Loading and Unloading Compression

“…In the final analysis, rock failure is a state instability phenomenon driven by energy [1], and the dynamic failure of rock is a result of the rapid release of elastic energy aggregated inside a rock when failure reaches the intensity limit [2][3][4]. Energy evolution runs through the entire process of rock deformation and failure.…”

“…Zhang et al researched the distribution law of the impact loading rate on energy dissipation and release of gabbro and marble [18]. Xie et al performed thermodynamic analysis of the rock deformation and failure process, revealed the internal relationship between rock failure and energy accumulation and release, defined concepts of unit dissipated energy, releasable strain energy, strength loss, and overall failure, and established rock strength and an overall failure criterion based on an energy dissipation and release principle [1]. Li et al did uniaxial compression experiments on coarsegrained rock under different strain rates, revealed the influence of the loading strain rate on strain energy dissipation and release of the rock, discussed the energy mechanism of the rock failure evolution, and indicated that when there was more dissipated energy under uniaxial compression before the peak and higher strength, the releasable elastic strain energy and release speed after peak were greater, the extensional penetrating rupture feature of rock was stronger, and the number of broken blocks was greater; energy dissipation caused rock failure, and strength loss and energy release led to macroscopic failure surface penetration and overall rock failure [19].…”

Mechanical Behavior of Red Sandstone under Incremental Uniaxial Cyclical Compressive and Tensile Loading

“…The considered dissipated energy in each loading cycle ( diss ) can be obtained by calculating the area defined by the hysteresis loop in the stress-strain curves [17]. Since the zone between the loading and unloading stress-strain curves represents the dissipated energy density [18], the dissipated energy diss can be expressed as [19] …”

The fractal characteristics and energy mechanism of crack propagation in tight reservoir sandstone subjected to triaxial stresses

“…propagation in sandstone under triaxial stress, we employed energy theories and principles to analyze the energy mechanism of crack propagation. The essence of the deformation and failure process of rock can be regarded as the process of energy dissipation and energy release (Chen et al, 2016;Peng et al, 2015;Xie et al, 2011;Xu et al, 2014 andTang et al, 2015). Based on energy principles, for an isothermal deformation process, the work done by external forces can be transferred into two categories of energy, that is, 1) the irreversible energy that is dissipated through the granular debonding and sliding of material elements causing irreversible material deterioration (or damage) and plastic deformation and 2) the releasable elastic strain energy that is stored in material elements responsible for the reversible elastic deformation of the material.…”