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E-book Rock Fracture Mechanics and Fracture Criteria

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Penilaian

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For rock engineering projects, the cutting and fragmenting of rocks has attracted much attention. Exploring the fracture characteristics of rocks is helpful in achieving efficient and sustainable excavation for mining and tunneling engineering. The frac-ture toughness of rocks is a crucial mechanical indicator that weighs the initiation and extension of cracks during the breaking process. The microwave-assisted rock-fragmentation approach, as a clean, efficient, and convenient method of rock frag-mentation, was adopted by Yang et al. [1] to investigate combined-mode I/II fracture properties of basalt under different irradiation times ranging from 0 to 300 s. An EGS (enhanced geothermal system) can effectively develop geothermal resources in HDR (hot dry rock). The HDR reservoir with massive fracture networks is expected to increase the contact regions between the injected water and rock masses and improve the geothermal output. Therefore, it is essential to understand the fracture mechanical properties of HDR reservoirs. Since granite is regarded as a typical rock type in geothermal energy extraction, Feng et al. [2] investigated the thermal effect on combined-mode I/II fracture behaviors of granite under different temperatures ranging from 20 °C to 600 °C. Shale rocks are characterized by extremely low porosity and permeability, and the abundant shale gas can be successfully extracted by the fracking (or hydraulic fracturing) technique. The fracking technique enhances the productivity and recovery of shale gas by creating high-conductivity fractures, requiring a thorough comprehension of fracture network formation. When the SIF (stress intensity factor) attains its critical state, the cracks become unstable and prop-agate rapidly, and the critical SIF can significantly affect the geometry of hydraulic fractures. As a central fracturing index, shale fracture toughness weighs the stress and displacement fields near the crack front, and controls the formation and distri-bution of hydraulic fracturing networks. Currently, the investigators have empha-sized on the evaluation of pure mode I fracture resistance for shale via the ENRBB (edge-notched rectangular beam bending) [3–5], ENSCB (edge-notched semicir-cular bending) [6–8], CCDC (centrally cracked disk compression) [9], and CCNDC (centrally chevron-notched disk compression) [10] testing methods, while the true mode-II fracture resistance of bedded shale has been effectively estimated via three shear approaches [11–13]. In fact, naturally cracked reservoirs generally undergo the complicated combined-mode I/II loading, and the resultant fracturing problems were analyzed by Suo et al. [14] and Wang et al. [15] using the ENSCB and HCCD (hollow center cracked disk) testing methods. For actual rock masses with randomly internal cracks, there are three essential fracture types, namely pure mode I (tension), pure mode II (shear), and pure mode III (tearing) which generate the opening, planar sliding, and nonplanar sliding deforma-tions of cracks respectively. In the fields of solid fracture mechanics and hydraulic fracturing, fracture toughness is referred to as an important parameter for evaluating the resistance of engineering materials to cracking growth [16–20]. To determine the magnitude of fracture toughness, different test specimens and loading configura-tions are devised and customized depending on engineering requirements [21–31]. Considering the economy and convenience of fracture testing, the SCB (semi-circular bending) specimen was designed by Chong and Kuruppu [32] as originators who concluded that this specimen can be readily manufactured from rock masses and is loaded by a common and straightforward three-point bending fixture. Under different SCB specimen sizes, the variations of mode-I fracture resistance could be success-fully predicted by a stress-based fracture model.

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Ketersediaan

Informasi Detail

Judul Seri

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No. Panggil

550 ZHA r

Penerbit

Singapore : Guizhou University., 2024

Deskripsi Fisik

119 hlm

Bahasa

English

ISBN/ISSN

9789819758227

Klasifikasi

550

Tipe Isi

text

Tipe Media

computer

Tipe Pembawa

online resource

Edisi

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Subjek

Earth Sciences

Info Detail Spesifik

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Pernyataan Tanggungjawab

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Versi lain/terkait

Lampiran Berkas

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