Dynamic Splitting Experimental Study on Sandstone at Actual High Temperatures under Different Loading Rates

Ping, Qi; Wu, Mingjing; Yuan, Pu; Hai-peng, SU; Zhang, Huan

doi:10.1155/2020/8867102

Cited by 5 publications

(5 citation statements)

References 29 publications

(30 reference statements)

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“…The relationships between temperature and the peak radial strain (Ping, Wu, et al, 2020) as well as the maximum absorbed energy are compared in Figures 12 and 13. From Figure 12, it can be seen that the peak radial strain increases with temperature at different strain rates, which is indicative of a transition from brittleness to ductility.…”

Section: Mechanical Properties Of Thermally Damaged Granite Under Dyn...mentioning

confidence: 99%

“…For this reason, it is necessary to study the dynamic tensile properties and failure characteristics of thermally damaged rocks to facilitate the construction of geothermal systems. Many scholars have conducted impact tests on rock samples using the Split Hopkinson Pressure Bar (SHPB) to study the strength (Hao et al, 2020; Mardoukhi et al, 2017), deformation (Ping, Wu, et al, 2020), and energy dissipation characteristics (Wang et al, 2018; Xu, Kang, et al, 2020) of rock samples subjected to high‐temperature treatment, including thermally treated intact Brazilian disc (BD) samples, cracked straight through Brazilian disc (CSTBD) samples, and notched semicircular bending (NSCB) samples. Because rocks are heterogeneously formed by polymerization of polyphase minerals, the thermal stress produced by thermal expansion of minerals weakens the contact between rock minerals, thus impairing the tensile properties of rocks.…”

Section: Introductionmentioning

confidence: 99%

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Mechanical properties and fracture surface roughness of thermally damaged granite under dynamic splitting

Qian,

Jia,

Mao

et al. 2023

Deep Underground Science and Engineering

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In order to understand the mechanical properties and the fracture surface roughness characteristics of thermally damaged granite under dynamic splitting, dynamic Brazilian splitting tests were conducted on granite samples after thermal treatment at 25, 200, 400, and 600°C. Results show that the dynamic peak splitting strength of thermally damaged granite samples increases with increasing strain rate, showing obvious strain‐rate sensitivity. With increasing temperature, thermally induced cracks in granite transform from intergranular cracks to intragranular cracks, and to a transgranular crack network. Thermally induced damages reduce the dynamic peak splitting strength and the maximum absorbed energy while increasing the peak radial strain. The fracture mode of the thermally damaged granite under dynamic loads is mode II splitting failure. By using the axial roughness index , the distribution ranges of the wedge‐shaped failure zones and the tensile failure zones in the fracture surfaces under dynamic Brazilian splitting can be effectively identified. The radial roughness index is sensitive to the strain rate and temperature. It shows a linear correlation with the peak splitting strength and the maximum absorbed energy and a linear negative correlation with the peak radial strain. can be used to quantitatively estimate the dynamic parameters based on the models proposed.

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Section: Mechanical Properties Of Thermally Damaged Granite Under Dyn...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mechanical properties and fracture surface roughness of thermally damaged granite under dynamic splitting

Qian,

Jia,

Mao

et al. 2023

Deep Underground Science and Engineering

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show abstract

“…Their study intriguingly suggested that varying impact speeds mitigated the adverse effects of temperature on sandstone strength. Furthermore, Ping et al 9 conducted dynamic compression tests on sandstone under real-time temperature conditions. Their conclusions highlighted the increasing brittleness of sandstone up to 400 °C, followed by a slight transition toward ductility up to 800 °C.…”

Section: Introductionmentioning

confidence: 99%

Experimental study on the quasi-static and dynamic tensile behaviour of thermally treated Barakar sandstone in Jharia coal mine fire region, India

Tripathi,

Khan,

Pain

et al. 2024

Sci Rep

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In the present study, the effect of mild to high-temperature regimes on the quasi-static and dynamic tensile behaviours of Barakar sandstone from the Jharia coal mine fire region has been experimentally investigated. The experimental work has been performed on Brazilian disk specimens of Barakar sandstone, which are thermally treated up to 800 °C. The quasi-static and dynamic split tensile strength tests were carried out on a servo-controlled universal testing machine and Split Hopkinson Pressure Bar (SHPB), respectively. Microscopic and mineralogical changes were studied through a petrographic investigation. The experimental results suggest the prevalence of both, static and dynamic loading scenarios after 400 °C. Up to 400 °C, the quasi-static and dynamic tensile strengths increased due to the evaporation of water, which suggests a strengthening effect. However, beyond 400 °C, both strengths decreased significantly as newly formed thermal microcracks became prevalent. The dynamic tensile strength exhibits strain rate sensitivity up to 400 °C, although it shows a marginal decline in this sensitivity beyond this temperature threshold. The Dynamic Increase Factor (DIF) remained constant up to 400 °C and slightly increased after 400 °C. Furthermore, the characteristic strain rate at which the dynamic strength becomes twice the quasi-static strength remains consistent until reaching 400 °C but steadily decreases beyond this temperature. This experimental study represents the first attempt to validate the Kimberley model specifically for thermally treated rocks. Interestingly, the presence of water did not have a significant impact on the failure modes up to 400 °C, as the samples exhibited a dominant tensile failure mode, breaking into two halves with fewer fragments. However, as temperature increased, the failure behaviours became more complex due to the combined influence of thermally induced microcracks and the applied impact load. Cracks initially formed at the centre and subsequently, multiple shear cracks emerged and propagated in the loading direction, resulting in a high degree of fragmentation. This study also demonstrates that shear failure is not solely dependent on the loading rate but can also be influenced by temperature, further affecting the failure mode of the sandstone.

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“…Gao et al [5] carried out 4 grades temperature treatment for Fangshan marble and conducted dynamic compression tests under dry and saturated conditions. Ping et al [6,7] studied the dynamic mechanical energy evolution characteristics of limestone under high temperature and carried out the experimental study on dynamic splitting tensile of high temperature sandstone under different loading rates. Experimental studies on wave characteristics and dynamic mechanical properties of granite after different high temperatures were conducted by the ultrasonic analyzer and SHPB device [8].…”

Section: Introductionmentioning

confidence: 99%

Influence of Two Cooling Methods on Dynamic Mechanical Properties of High Temperature Sandstone

Ping

Diao

et al. 2021

Shock and Vibration

Self Cite

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To study the influence of different cooling methods on dynamic mechanical properties of high temperature rock, both natural cooling and water cooling were used to cool high temperature (100°C∼1000°C) coal mine sandstone to room temperature (20°C). Basic physical parameters of sandstone were measured, and impact compression tests were carried out by using the SHPB test device. Comparative analysis shows that the volume expansion rate, mass loss rate, density reduction rate, and P-wave velocity reduction rate of sandstone specimens are positively correlated with the temperature in a quadratic function. The deteriorate rate of physical parameters of water cooling sandstone specimens is slightly larger than that of natural cooling. The variation of dynamic stress-strain curves is basically consistent. Compaction stage of water cooling is slightly larger than that of natural cooling. With the increase in temperature, dynamic compressive strength of sandstone specimens first increases, then decreases, and reaches maximum at 300°C. Subsequently, dynamic compressive strength decreases in a quadratic function with the temperature, and dynamic compressive strength of water cooling sandstone specimens is significantly lower than that of natural cooling. The dynamic elastic modulus also first increases and then decreases with the temperature and reaches maximum at 300°C. The dynamic elastic modulus of water cooling sandstone specimens is lower than that of natural cooling, but they are roughly the same at 1000°C. Dynamic strain increases in a quadratic function with the temperature, and dynamic strain of water cooling sandstone specimens is greater than that of natural cooling. The impact failure of sandstone specimens is intensified with the temperature, and the failure degree of water cooling is greater than that of natural cooling.

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Dynamic Splitting Experimental Study on Sandstone at Actual High Temperatures under Different Loading Rates

Cited by 5 publications

References 29 publications

Mechanical properties and fracture surface roughness of thermally damaged granite under dynamic splitting

Mechanical properties and fracture surface roughness of thermally damaged granite under dynamic splitting

Experimental study on the quasi-static and dynamic tensile behaviour of thermally treated Barakar sandstone in Jharia coal mine fire region, India

Influence of Two Cooling Methods on Dynamic Mechanical Properties of High Temperature Sandstone

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