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| Titel |
Study on ground subsidence development during and after underground coal gasification |
| VerfasserIn |
Hong Tian, Thomas Kempka, Martin Feinendegen, Martin Ziegler |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250046390
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| Zusammenfassung |
| Underground coal gasification (UCG) is currently world-wide revived as a result of its
benefits of increasing recoverable coal reserves, promising economics and environmental
friendliness, especially when combined with geological carbon dioxide storage in the gasified
coal seams and surrounding rocks. As one of the main environmental risks, the development
of ground subsidence has to be studied in detail.
Generally, geological and geotechnical properties of strata as well as operational
processes control the overburden collapse and induced ground subsidence for conventional
mining. However, a significant distinction between UCG and mining is that rock masses
during UCG are exposed to extremely high temperatures. This may result in significant
changes of the rock properties, affecting the extent of the overburden deformation as well as
the coal gasification process. To investigate the thermo-mechanical properties, the
temperature dependent uni- and tri-axial tests in the range of 20-C to 1000-C have been
carried out on rocks from German coal mining areas. The experimental results are used for
the development of a thermo-mechanical constitutive model and the parameterization of
numerical models.
Based on a great amount of geological information and samples from German hard coal
mining districts, our research on ground subsidence involves:
Verification of the thermo-mechanical constitutive relationship best-suitable for
the combined processes;
Sensitivity analyses of the layout of the gasified parts of the coal seam as well as
its depth and the characteristics of surrounding rocks;
Estimation of the impact of CO2 storage in the vicinity of the gasification area;
Prediction of the long-term development of subsidence taking into account the
rock mechanical behaviour after high temperatures; and
Validation of the numerical studies by literature data.
When the effects of high temperatures on rocks are incorporated into modelling, the simulation
of UCG in terms of mechanical aspects may be more realistic and reliable. Our research can
be of benefit to the estimation of roof deformation and ground subsidence as well as
the operation control of UCG in the preliminary design phase for a commercial
scale. |
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