Physical Properties of Sandstones After High Temperature Treatment

Tian, Hong; Kempka, Thomas; Xu, Nengxiong; Ziegler, Martin

doi:10.1007/s00603-012-0228-z

Cited by 202 publications

(71 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The impacts of enhanced and high temperatures on thermo-mechanical rock properties have been investigated during the last decades to improve process quantification and prediction in different engineering topics, including nuclear waste disposal, geothermal heat recovery and UCG [14,15,38,48,54,55]. Hereby, the linear thermal expansion coefficient was identified as one of the key parameters, governing volumetric and stress changes in rocks exposed to high temperatures (≥200 • C).…”

Section: Discussionmentioning

confidence: 99%

“…Site-specific coupled thermo-mechanical processes occurring in rocks adjacent to a deep UCG reactor are generally not well known in the field, because of the difficulty to quantify all occurring chemical reactions during the UCG process and their effects on UCG reactor size and shape [12]. Current knowledge on these processes is mainly based on laboratory experiments [13][14][15][16][17][18][19][20][21][22][23] and a few successful UCG field trails. Since the 1930s, more than 50 pilot-scale UCG operations have been carried out worldwide.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Fault Reactivation Can Generate Hydraulic Short Circuits in Underground Coal Gasification—New Insights from Regional-Scale Thermo-Mechanical 3D Modeling

et al. 2016

Self Cite

View full text Add to dashboard Cite

Underground coal gasification (UCG) has the potential to increase worldwide coal reserves by utilization of coal deposits not mineable by conventional methods. This involves combusting coal in situ to produce a synthesis gas, applicable for electricity generation and chemical feedstock production. Three-dimensional (3D) thermo-mechanical models already significantly contribute to UCG design by process optimization and mitigation of the environmental footprint. We developed the first 3D UCG model based on real structural geological data to investigate the impacts of using isothermal and non-isothermal simulations, two different pillar widths and four varying regional stress regimes on the spatial changes in temperature and permeability, ground surface subsidence and fault reactivation. Our simulation results demonstrate that non-isothermal processes have to be considered in these assessments due to thermally-induced stresses. Furthermore, we demonstrate that permeability increase is limited to the close reactor vicinity, although the presence of previously undetected faults can introduce formation of hydraulic short circuits between single UCG channels over large distances. This requires particular consideration of potentially present sub-seismic faults in the exploration and site selection stages, since the required pillar widths may be easily underestimated in presence of faults with different orientations with respect to the regional stress regime.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Fault Reactivation Can Generate Hydraulic Short Circuits in Underground Coal Gasification—New Insights from Regional-Scale Thermo-Mechanical 3D Modeling

et al. 2016

Self Cite

View full text Add to dashboard Cite

show abstract

“…Temperature is one of the key factors that influence the microstructure, and the physical and mechanical properties of rocks; moreover, these properties are highly significant for rock mass classification and the design of structures either upon or inside the rock [9][10][11]. In addition, rock damage which has been formed previously continues existing in the rock and represents a "fingerprint" of the entire loading history [12].…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation of mechanical properties and energy features of granite after heat treatment under different loading paths

Zhang

Kang

2017

Teh. vjesn.

View full text Add to dashboard Cite

EXPERIMENTAL INVESTIGATION OF MECHANICAL PROPERTIES AND ENERGY FEATURES OF GRANITE AFTER HEAT TREATMENT UNDER DIFFERENT LOADING PATHSJunwen Zhang, Xu Chen, Hengyi KangOriginal scientific paper Temperature and loading history are the two main factors that influence rock microstructure and physical and mechanical properties. To explore the influence of heat treatment and loading path on mechanical properties and energy features of granite, granite samples were first heat-treated at 25 °C, 300 °C, 600 °C, and 900 °C. Then, 12 groups of triaxial compression experiments were placed under three loading paths, as follows: uniaxial compression, conventional triaxial compression, and confining pressure unloading. Mechanical properties and energy features in the deformation and failure process based on these experimental results were systematically compared and analyzed. Results demonstrate that Young's modulus, uniaxial compressive strength, and triaxial compressive strength increased in the temperature range of 25 °C to 300 °C, but decreased in the temperature range of 300 °C to 900 °C. Under the same loading path, the gaps among total absorbed energy, dissipated energy, and elastic strain energy widened with increasing temperature from 25 °C to 900 °C. At the same temperature, the energy features' gap under confining pressure unloading is between uniaxial and triaxial compression. The conclusions drawn in this study provide a significant reference for the design and construction of rock engineering exposed to high temperature. Keywords: energy features; heat treatment; loading paths; triaxial compression Eksperimentalno ispitivanje mehaničkih svojstava i energetskih svojstava granita nakon toplinske obrade pri različitom načinu opterećenjaIzvorni znanstveni članak Povijest temperature i opterećenja dva su glavna čimbenika koji utječu na mikrostrukturu stijene i fizikalna i mehanička svojstva. Da bi se istražio utjecaj toplinske obrade i opterećenja na mehanička svojstva i energetske značajke granita, uzorci granita najprije su toplinski obrađeni na 25 °C, 300 °C, 600 °C i 900° C. Zatim je 12 skupina eksperimenata troosnog sabijanja podvrgnuto opterećenju na tri načina, kako slijedi: jednoosno sabijanje, konvencionalno troosno sabijanje i ograničeno tlačno rasterećenje. Sustavno se uspoređuju i analiziraju mehanička svojstva i značajke energije u procesu deformacije i oštećenja na temelju tih eksperimentalnih rezultata. Rezultati pokazuju da su Youngov modul, jednoosna tlačna čvrstoća i troosna tlačna čvrstoća porasli u temperaturnom području od 25 °C do 300 °C, ali su se smanjili u temperaturnom području od 300 °C do 900 °C. Pod istim načinima opterećenja, razlike između ukupne apsorbirane energije, raspršene energije i elastične energije naprezanja povećale su se s porastom temperature od 25 °C do 900 °C. Pri istoj temperaturi, razlika između energetskih značajki pod rasterećenjem ograničenim tlakom je između jednoosnog i troosnog sabijanja. Zaključci izneseni u ovoj studiji pružaju značajnu referencu za projektiranje...

show abstract

“…The stability of the strata is compromised when exposed to high temperatures. The geomechanical properties of the rock suffer a substantial damage when exposed to high temperatures [1][2][3][4][5]. Studies conducted on various rock types suggest that the properties are highly susceptible to change in the presence of extreme temperatures.…”

Section: Introductionmentioning

confidence: 99%

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)

View full text Add to dashboard Cite

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.

show abstract

Physical Properties of Sandstones After High Temperature Treatment

Cited by 202 publications

References 12 publications

Fault Reactivation Can Generate Hydraulic Short Circuits in Underground Coal Gasification—New Insights from Regional-Scale Thermo-Mechanical 3D Modeling

Fault Reactivation Can Generate Hydraulic Short Circuits in Underground Coal Gasification—New Insights from Regional-Scale Thermo-Mechanical 3D Modeling

Experimental investigation of mechanical properties and energy features of granite after heat treatment under different loading paths

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

Contact Info

Product

Resources

About