Cracking and Stress–Strain Behavior of Rock-Like Material Containing Two Flaws Under Uniaxial Compression

Advances in Civil Engineering

et al. 2018

During the reservoir operation process, the long-term security and stability of the bank slope is affected by dynamic response characteristics of its seismic action directly. Aimed at the typical bank slope existing in the actual reservoir environment, an experiment considering reservoir water level fluctuation and soaking-air-drying cyclic water-rock interaction has been designed and conducted while the cyclic loading test was performed in different water-rock cycles. Research results indicate the following: Firstly, in the process of water-rock interaction, the dynamic characteristics of sandstone show evident degradation trend, with the increase of the damping ratio and Poisson's ratio and decrease of dynamic elastic modulus, and the former six water-rock cycle degradation effects are particularly obvious. Secondly, the numerical analog computation analysis of dynamic response in typical bank slope shows that as the water-rock interaction period is increased, the dynamic response of the slope hydro-fluctuation belt zone increases gradually, while the other parts weaken. irdly, under the long-term water-rock interaction process, the hydrofluctuation belt zone gradually becomes a "soft layer" which is sensitive to the earthquake effect and dynamic response, resulting in a direct influence on long-term seismic performance of the bank slope. erefore, it is necessary to make better protection for the bank slope hydro-fluctuation belt zone.

Section: E Cyclic Loading and Unloading Test Schemementioning

confidence: 99%

The Dynamic Response Law of Bank Slope under Water‐Rock Interaction

Zhang

Deng

Advances in Civil Engineering

et al. 2018

“…Despite the wealth of the studies on blast induced rock mass damage and blast induced rock mass crack initiation and propagation, it is far from complete for study of blast induced crack propagation and damage accumulation in rock mass containing initial damage composed of inherent geological discontinuities and previous multiblast induced damage [28]. The incomplete knowledge of the effect of small blasthole diameter blasting on rock mass containing initial damage hinders the estimate of long-term stability of the structure and the surrounding rock mass in that case, indicating the significance of investigating this field of research.…”

Section: Introductionmentioning

confidence: 99%

Blast Induced Crack Propagation and Damage Accumulation in Rock Mass Containing Initial Damage

Zhao

et al. 2018

Shock and Vibration

Self Cite

Blast induced rock mass damage and crack propagation play important roles in structure safety and stability in mining, quarrying, and civil constructions. This paper focuses on the effect of small blasthole diameter blast on crack propagation and damage accumulation in water-bearing rock mass containing initial damage composed of inherent geological discontinuities and previous multiblast induced damage. To elucidate this effect, theoretical analysis of calculation method for several important blast influencing factors is firstly presented. Secondly, definition of a practical damage variable using ratio of longitudinal wave velocity in rock mass before blast occurrence to that after blast occurrence and derivation of a damage accumulation calculation equation accounting for initial damage and blasting effect are described. Lastly, a detailed description of the conducted in situ blast tests and plan layout of the sonic wave monitoring holes is reported. The results indicate that blast activates and then extends the initial cracks in rock mass, leading to accumulation of rock mass damage. The rock mass damage accumulation can be conveniently quantified using the proposed damage variable. When the damage variable reaches its threshold of 0.19, occurrence of damage in the surrounding rock mass is indicated. It is also found that the blast induced rock mass damage extent and the blast induced vibration velocities decrease nonlinearly with increasing the distance between blast source and monitoring position.

“…Cracks will interact with each other, and the cracking behavior of rock materials critically depends on the crack interaction [1]. In order to improve the understanding of fracture mechanism of brittle materials with multiple cracks, abundant theoretical and experimental studies have been conducted on rock materials containing two cracks [2][3][4].…”

Section: Introductionmentioning

confidence: 99%

Study on the Interaction of Collinear Cracks and Wing Cracks and Cracking Behavior of Rock under Uniaxial Compression

Advances in Civil Engineering

Zhao

et al. 2018

Self Cite

is paper investigates the crack interaction, initiation, and propagation rules of rock-like materials containing two collinear cracks. Based on the Kachanov method, the formulations for stress intensity factors (SIFs) of two collinear cracks and two winged cracks are derived, respectively. e influences of bridge ligament and crack length on the crack interaction are analyzed theoretically. e results show that the propagation of a long crack is independent of crack interaction when d ≥ a 2 and the same rule applies for a short crack when d ≥ a 1 . With the growth of wing cracks, the SIF of wings first remarkably decreases and then it tends toward a steady value. Subsequently, the propagation of collinear cracks and cracking processes under uniaxial compression are analyzed experimentally and numerically. Both the experimental results and simulation results demonstrate that shear cracks tend to initiate and propagate at higher inclination angle. e crack coalescence is affected by the inclination angle of bridge ligament. For increasing the inclination angle, the crack coalescence varies from wing crack failure to shear crack coalescence. As bridge ligament increases, the crack coalescence varies from shear crack coalescence to shear-wing crack coalescence and then to wing crack failure.