Influence of thermal treatment on mode I fracture toughness of certain Indian rocks

Mahanta, Bankim; Singh, T. N.; Ranjith, P.G.

doi:10.1016/j.enggeo.2016.06.008

Cited by 187 publications

(41 citation statements)

References 62 publications

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“…However, the studies carried out on sedimentary rocks affirm with the decrease of the mechanical properties after a certain temperature limit. This limit, also known as the critical temperature zone (CTZ), indicate the deterioration of internal structure of rock due to extensive expansion and creation of inter and intragranularmicrocracks [8,10]. The CTZ for Dholpur sandstone can therefore be confirmed at temperatures between 300-500°C.…”

Section: Resultsmentioning

confidence: 94%

“…Also it can be noticed that, at temperatures above 500°C, the rock behaves like a plastic material undergoing ductile deformations. This is known as transformation plasticity and can be seen in all the rocks studied in the literature [1,3,6,8,9,11]. Images obtained from a scanning electron microscope (SEM) were used to observe and better appreciate the effect of thermal treatment.…”

Section: Resultsmentioning

confidence: 99%

“…Studies conducted on various rock types suggest that the properties are highly susceptible to change in the presence of extreme temperatures. Duration of exposure to high temperatures also accounts for the change in the mechanical properties of the rock [6][7][8][9][10][11]. Rock, as every other material, expands when subjected to heating.…”

Section: Introductionmentioning

confidence: 99%

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Elastic modulus of thermally treated fine grained sandstone using non-contact laser extensometer

Sirdesai¹,

Mahanta²,

Ranjith³

et al. 2016

Proceedings of the Conference on Recent Advances in Rock Engineering (RARE 2016)

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Abstract-Processes such as Underground Coal Gasification (UCG), Enhanced Oil Recovery (EOR) and underground disposal of nuclear waste involve the exposure of the surrounding rocks to extreme temperatures. At such high temperatures, the rock suffers substantial structural damage due to the anisotropy in the geotechnical properties of its constituent minerals. Due to variable thermal expansion within minerals, thermal stresses are generated in the rock microstructure which cause change in the fracture pattern. New cracks may develop and pre-existing one may migrate and widen further; thereby reducing the mechanical strength of the rock. In this study, an attempt has been made to study the elastic modulus of thermally treated fine grained sandstone from the Dholpur district of Rajasthan. The elastic modulus was measured by using a MTS LX-Laser Extensometer. The rock specimens were thermally treated at various temperatures for a fixed duration. The change in the rock microstructure was studied viewing the rock specimen under a scanning electron microscope.

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Section: Resultsmentioning

confidence: 94%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Elastic modulus of thermally treated fine grained sandstone using non-contact laser extensometer

Sirdesai¹,

Mahanta²,

Ranjith³

et al. 2016

Proceedings of the Conference on Recent Advances in Rock Engineering (RARE 2016)

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“…More and more researchers have studied the influence of temperature on the physical and mechanical properties of salt rock. It was found that both uniaxial compressive strength and axial strain increase with the increasing temperature; however, the tangent modulus decreases with the increasing temperature . By extension, researchers studied the influence of high temperature on the peak strength, elastic modulus, and damage characteristics and compared the stress‐strain curves of different sandstones between normal temperature and the high temperature of 950°C .…”

Section: Introductionmentioning

confidence: 99%

Effect of thermal cycling and hydro‐thermal cycling on physical and mechanical properties of sandstone

Liu

Tian

et al. 2019

Energy Science & Engineering

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Thermal storage of sandstone is widely distributed in sedimentary basins in China with a very high degree of exploitation and utilization, while the low recharge rate is the bottleneck of its sustainable development. A new method is proposed to discover the physical and mechanical behaviors of sandstone after thermal cycling and hydro‐thermal cycling treatments in this study. The stress‐strain curves, strength, failure behavior, acoustic emission (AE), P‐wave velocity, density features, X‐ray, and microscope images of specimens are analyzed in detail to investigate and describe the differences of the sandstone after the two different experimental treatments. The results indicate that multiple thermal cycling and hydro‐thermal cycling have an obvious effect on the compaction stage of sandstone at the temperature of 100°C. Meanwhile, strengths and Young's modulus of specimens after hydro‐thermal cycling treatment decrease with cycling times and the reduce degree is greater than that of the thermal cycling treatment on sandstone. The brittleness of the sandstone decreases as the hydro‐thermal cycling number increases from 0 to 15, and the influence of hydro‐thermal cycling is greater than that of thermal cycling on sandstone. In addition, based on the limited cycling experimental results, the action of the thermal cycling leaded the thermal stress of the crystal to nonuniform, which leaded to micronarrow and sharp cracks in specimens. Furthermore, the action of the hydro‐thermal cycling generated thermal stress and ablation coupling effect, which leaded wider and rounder cracks than that of the specimen under thermal cycling condition. Finally, it indicates that hydro‐thermal cycling has a greater effect than that of the thermal cycling treatment on the physical and mechanical properties of sandstone on the macro‐ and microlevels.

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“…Decrease in the tensile strength of rock by increasing temperature has been reported by several researchers [5,12]. Mahanta et al [13] studied the effect of temperature on the mode I fracture toughness of three different Indian rocks. The results show that by increasing the temperature up to 100 ˚C, the fracture toughness of all three rocks increases considerably.…”

Section: Introductionmentioning

confidence: 99%

Experimental study of the dynamic indentation damage in thermally shocked granite

Mardoukhi¹,

Hokka²,

Kuokkala³

2018

RakMek

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Summary. This paper presents an experimental procedure to study the effects of pre-existing cracks and damage on the rock behavior under dynamic indentation. To gain better understanding on the mechanism involved in percussive-rotary drilling procedure, a modified Split Hopkinson Pressure Bar device was used to carry out dynamic indentation tests, where rock drill buttons were impacted on rock samples with dimensions of 30 cm × 30 cm × 30 cm. Before the mechanical testing, the samples were thermally shocked using a plasma spray gun for periods of 3, 4, and 6 seconds. The plasma gun produces a powerful heat shocks on the rock sample, and even short exposures can change the surface structure of the samples and provide samples with different crack patterns and surface roughness for experimental testing. The effects of the heat shock damage on the dynamic indentation behavior of the rock were characterized with singleand triple-button indentation tests. The specific destruction work was used to characterize the effects of heat shocks on the material removal during dynamic indentation. The results show that the force-displacement response of the rock does not change much even if the rock surface is severely damaged by the heat shock, however, the destruction work decreases significantly. This means that the same loading removes more volume if the material surface is pre-damaged, and that the efficiency of the indentation process cannot be evaluated from the bit-rock interaction forces alone. The presented experimental framework can be a useful tool for the verification of numerical models where the rock microstructure and especially the microcracks are essential.

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Influence of thermal treatment on mode I fracture toughness of certain Indian rocks

Cited by 187 publications

References 62 publications

Elastic modulus of thermally treated fine grained sandstone using non-contact laser extensometer

Elastic modulus of thermally treated fine grained sandstone using non-contact laser extensometer

Effect of thermal cycling and hydro‐thermal cycling on physical and mechanical properties of sandstone

Experimental study of the dynamic indentation damage in thermally shocked granite

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