Experimental investigation on hydraulic fracturing of granite specimens with double flaws based on DIC

Zhao, Cheng; Xing, Jinquan; Zhou, Yimeng; Shi, Zhenming; Wang, Gang

doi:10.1016/j.enggeo.2020.105510

Cited by 72 publications

(10 citation statements)

References 22 publications

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“…The results suggested that in addition to dilatant shear slip (which has been recognized as an important permeability creation mechanism during reservoir stimulation), propagation and coalescence of pre-existing flaws significantly contribute to reservoir permeability creation during low injection pressure stimulation in flawed rocks. Zhao et al 106 presented an experimental investigation on hydraulic fracturing of granite specimens with double flaws based on DIC. Results showed that the crack types in the hydraulic fracturing tests were primarily Type I or Type Ib tensile cracks.…”

Section: Crack Initiation and Growth In Flawed Rocks Due To Temperature Treatmentsmentioning

confidence: 99%

“…Results showed that the crack types in the hydraulic fracturing tests were primarily Type I or Type Ib tensile cracks. The process of strain localization zones (SLZs) revealed the physical process of the hydraulic fracturing 106 : SLZs initiate at or near pre-existing flaw tips before fracturing, and then cracks initiate and propagate along the SLZs.…”

Section: Crack Initiation and Growth In Flawed Rocks Due To Temperature Treatmentsmentioning

confidence: 99%

See 1 more Smart Citation

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

Zhou

Zhang

Yang

et al. 2021

Fatigue Fract Eng Mat Struct

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Section: Crack Initiation and Growth In Flawed Rocks Due To Temperature Treatmentsmentioning

confidence: 99%

Section: Crack Initiation and Growth In Flawed Rocks Due To Temperature Treatmentsmentioning

confidence: 99%

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

Zhou

Zhang

Yang

et al. 2021

Fatigue Fract Eng Mat Struct

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show abstract

“…For example, Gao et al [39,40] obtained the fracture propagation parameters such as the location of the crack tip, propagation velocity, and the fracture initiation/ propagation toughness using the deformation fields in DIC analysis. Zhao et al [41] analyzed the cracks' mechanism using the strain field around crack tips and summarized the crack evolution characteristics in the hydraulic fracturing process. Moreover, Miao et al [42] distinguished the cracking process of flawed sandstone with different infilling materials by quantifying the displacement information between the observation points enclosing the flaws.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Mechanical Response, Cracking Behavior, and Stress Intensity Factors of Cement Mortar Specimens with Open and Closed Flaws

Wang

Shi

Wang

et al. 2022

Shock and Vibration

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Major civil and military infrastructures are usually located in mountainous areas with complex geological structures. When subjected to impact loads caused by operational blasting or seismic activities, the inherent flaws or joints in the hosting rock mass may grow irreversibly and eventually and cause the entire structure to collapse. It is, therefore, desirable to understand the mechanical and cracking behaviors of flawed rock structures under dynamic loads. In this work, the cement mortar is used to make the plate specimens, and two different types of flaws, i.e., the open and the closed (resin-filled) flaws, with different inclination angles from 0° to 90° with respect to the loading direction are prefabricated. The nominal strength, crack initiation, and failure characteristics of the specimens under different loading rates are investigated using the split Hopkinson bar (SHPB) system in conjunction with the digital image correlation (DIC) technique. The results indicate that the dynamic nominal strength of both two types of specimens shows similar loading rate and flaw angle dependency, specifically, monotonically increasing with the increase of the loading rate while increasing first and then decreasing with increasing the flaw inclination angle. The strength of specimens with an open flaw is obviously lower than that of the specimens with a closed flaw at a similar loading rate. Besides, the failure mode of specimens with an open flaw is mainly an X-shaped tensile or tensile-shear mixed form regardless of the flaw inclination, whereas the resin-filled flawed specimens always fail in the form of an atypical X-shaped shear pattern with obvious randomness. Moreover, the stress field around the crack tip is carefully extracted based on the obtained displacement field from DIC analysis; the stress intensity factors at crack initiation onset also show flaw inclination- and loading rate-dependent behavior. The strength, cracking behavior, and stress field around the tip during the dynamic loading are closely related to the friction effect between the flaw surfaces. The findings in this work provide some basic insights into the cracking mechanism of rock with open and closed flaws under dynamic loading conditions.

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“…Wang et al [17] conducted fatigue tests on granite after freeze-thaw treatment and found that the frost heave force generated by water-ice phase transition led to the accumulation of damage at the crack tip. Zhao et al [18] studied the evolution law of hydraulic fracture through strain localization evolution of double-crack granite under hydraulic fracturing based on digital image correlation. Ke et al [19,20] found the internal damage of sandstone caused by freeze-thaw weathering and established a unified model to describe the deterioration of dynamic mechanical strength of rock materials during repeated freeze-thaw weathering.…”

Section: Introductionmentioning

confidence: 99%

Study on the Influence of Different Prophase Stress Levels on the Fatigue Damage Characteristics of Granite

Wang

Xue

Sha

et al. 2021

Shock and Vibration

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In order to reveal the influence of prophase stress levels on the fatigue damage characteristics of granite, uniaxial fatigue tests of granite with different prophase stress levels were carried out on the basis of the MTS 815.04 rock mechanics test system. The results show that, under the same number of cycles, the failure degree increases with the increase of the prophase stress level. Under the low upper limit of cyclic stress, the tangent modulus and dissipated energy increase significantly with the increase of prophase stress level at the early stage of the cycle loading, while the increasing trend is not obvious with the increase of prophase stress level at the late stage. Under the high upper limit of cyclic stress, the tangent modulus and dissipated energy are less affected by the prophase stress level. The development trend of elastic release energy is not obvious with the increase of prophase stress level, which is less affected by the number of cycles. From the damage parameters defined by dissipative energy, under the low upper limit of cyclic stress, the initial damage is less affected by the prophase stress level. With the increase of the number of cycles, the influence of the prophase stress level on the development trend of the damage variable increases gradually. And the development trend of damage variables shows “C-shaped” damage.

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Experimental investigation on hydraulic fracturing of granite specimens with double flaws based on DIC

Cited by 72 publications

References 22 publications

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

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

Dynamic Mechanical Response, Cracking Behavior, and Stress Intensity Factors of Cement Mortar Specimens with Open and Closed Flaws

Study on the Influence of Different Prophase Stress Levels on the Fatigue Damage Characteristics of Granite

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