Combined effects of increasing temperature and confining pressure on the fracture toughness of clay bearing rocks

Funatsu, Takahiro; Seto, Makoto; Shimada, Hideki; Matsui, Kikuo; Kuruppu, Mahinda

doi:10.1016/j.ijrmms.2004.02.008

Cited by 201 publications

(73 citation statements)

References 12 publications

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“…By performing controlled thermal cracking experiments, the influence of microcrack density on K IC has been quantitatively investigated by several researchers (ATKINSON, 1984;MEREDITH and ATKINSON, 1985;BALME et al, 2004;FUNATSU et al, 2004;. Results of these studies are consistent in showing that thermal cracking significantly reduces the mechanical strength, elastic wave velocities, and fracture toughness in rock, including granite.…”

Section: Introductionmentioning

confidence: 93%

Fracture Toughness and Fracture Roughness Interrelationship in Thermally treated Westerly Granite

Nasseri

Tatone

Grasselli

et al. 2009

Pure appl. geophys.

102

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This paper presents an experimental work aimed at assessing the correlation between fracture toughness (K IC ) and fracture roughness for a series of Westerly granite specimens thermally treated up to 850°C. Mode I fracture toughness as a function of thermal treatment is determined using Cracked Chevron Notched Brazilian Disc specimens. The degree of roughness of the resultant fracture surfaces is analyzed with the aid of a high accuracy, high precision stereo-topometric measurement system. Roughness and toughness values display a negative correlation as a function of temperature. Fracture toughness decreases with increasing temperature due to the gradual opening of grain-grain boundaries in response to thermal stresses. Mode I fractures preferentially follow these weakened grain-grain boundaries, which in addition to the thermal expansion of individual grains, result in rougher failure profiles with increasing temperature. At low temperature, a distinct anisotropy in roughness was observed in all fracture surfaces with higher roughness values perpendicular to the direction of fracture propagation. However, higher treatment temperatures resulted in the homogenization of fracture roughness in all directions. These results confirm the important link among petrofabric analysis, fracture toughness, and fracture roughness in response to thermal treatment.

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Section: Introductionmentioning

confidence: 93%

Fracture Toughness and Fracture Roughness Interrelationship in Thermally treated Westerly Granite

Nasseri

Tatone

Grasselli

et al. 2009

Pure appl. geophys.

102

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show abstract

“…Temperature may be set at a predetermined level and maintained until the specimen is heated uniformly (Funatsu et al 2004;Kuruppu and Seto 2001). They may be controlled independently from the axial load application that would perform the 3-point bend loading of the specimen.…”

Section: Experimental Set-upmentioning

confidence: 99%

ISRM-Suggested Method for Determining the Mode I Static Fracture Toughness Using Semi-Circular Bend Specimen

Kuruppu

Ayatollahi

Chong

et al. 2013

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The International Society for Rock Mechanics has so far developed two standard methods for the determination of static fracture toughness of rock. They used three different core based specimens and tests were to be performed on a typical laboratory compression or tension load frame. Another method to determine the mode I fracture toughness of rock using semicircular bend specimen is herein presented. The specimen is semicircular in shape and made from typical cores taken from the rock with any relative material directions noted. The specimens are tested in three-point bending using a laboratory compression test instrument. The failure load along with its dimensions is used to determine the fracture toughness. Most sedimentary rocks which are layered in structure may exhibit fracture properties that depend on the orientation and therefore measurements in more than one material direction may be necessary. The fracture toughness measurements are expected to yield a size-independent material property if certain minimum specimen size requirements are satisfied.

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“…This geometry was proposed by CHONG (1987) and received extensive study by LIM et al (1994 a,b,c) and experimental attention from KRISHNAN et al (1998) andFUNATSU et al (2004). The specimen and configuration for testing are shown in Figure 6(a).…”

Section: Geometry Related To Ccnbd: 2 -Semi-circular Specimen Under Tmentioning

confidence: 99%

An Update on the Fracture Toughness Testing Methods Related to the Cracked Chevron-notched Brazilian Disk (CCNBD) Specimen

Fowell

Dowd

2006

Pure appl. geophys.

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This paper reviews the use of the cracked Chevron-notched Brazilian disc (CCNBD) for fracture toughness testing. Theoretical and experimental backgrounds of the method are described. Some issues regarding the current development (i.e., recalibration) of the specimen geometry are presented and discussed. A number of geometries related to the CCNBD proposed recently for fracture toughness testing of rock are then introduced and commented on.

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Combined effects of increasing temperature and confining pressure on the fracture toughness of clay bearing rocks

Cited by 201 publications

References 12 publications

Fracture Toughness and Fracture Roughness Interrelationship in Thermally treated Westerly Granite

Fracture Toughness and Fracture Roughness Interrelationship in Thermally treated Westerly Granite

ISRM-Suggested Method for Determining the Mode I Static Fracture Toughness Using Semi-Circular Bend Specimen

An Update on the Fracture Toughness Testing Methods Related to the Cracked Chevron-notched Brazilian Disk (CCNBD) Specimen

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