A comprehensive and systematic research on the forcible thawing temperature field formed by a single heat transfer pipe with unsteady outer surface temperature was carried out by analytic computation according to the ...A comprehensive and systematic research on the forcible thawing temperature field formed by a single heat transfer pipe with unsteady outer surface temperature was carried out by analytic computation according to the theory of similitude. The distribution law of thawing temperature field, calculation formulas of thawing radius b, heat flux density q and average thawing temperature T were obtained. It theoretically explains that the main influential factors of thawing radius b, heat flux density q and thawing average temperature T are K,f, Lx and co（l）, but Lc affects little. Finally, based on the forcible thawing project of Hulusu air shaft lining, the field data indicate that the analytical formulas of this article are comparatively accurate.展开更多
Identification of the meta-instable stress state and study of its mechanism and evolution of relevant physical fields would be of great significance for determination of potential seismic risks and estimation of criti...Identification of the meta-instable stress state and study of its mechanism and evolution of relevant physical fields would be of great significance for determination of potential seismic risks and estimation of critical times. In laboratory experiments, that the specimen enters the meta-instable is marked by accelerated stress release. Could we use the experimental result to identify the earthquake in natural conditions? Because the observational data from one station can only reflect the stress state beneath this station, the key problem for identification of the meta-instability is how to recognize regional stress state through observational data from many stations. In this work, we choose the evolution of the temperature field over varied deformation stages during a stick-slip event on a 5 bending fault as an example, and attempt to find the response features of the physical quantity when the fault enters the meta-instable state. We discuss the characteristics of stages for the stress build-up, stress-time process deviating from linearity before instability, meta-instability, instability, and post-instability, respectively. The result shows that the fault instability slide is a conversion process from independent activities of each fault segment to synergism activity. The instability implies completion of the synergism. The stage deviating from linearity is the onset of stress release, and it is also the onset of the synergism. At the meta-instability stages, stress release becomes dominant, while the synergism tends to finish. Therefore, the analysis of the regional overall stress state should not start from individual stations, and instead it should begin with the evolution of the whole deformation field.展开更多
基金Supported by the Natural Science Foundation of China （40801032）
文摘A comprehensive and systematic research on the forcible thawing temperature field formed by a single heat transfer pipe with unsteady outer surface temperature was carried out by analytic computation according to the theory of similitude. The distribution law of thawing temperature field, calculation formulas of thawing radius b, heat flux density q and average thawing temperature T were obtained. It theoretically explains that the main influential factors of thawing radius b, heat flux density q and thawing average temperature T are K,f, Lx and co（l）, but Lc affects little. Finally, based on the forcible thawing project of Hulusu air shaft lining, the field data indicate that the analytical formulas of this article are comparatively accurate.
基金supported by the National Natural Science Foundation of China(Grant Nos. 40872129, 41172180)
文摘Identification of the meta-instable stress state and study of its mechanism and evolution of relevant physical fields would be of great significance for determination of potential seismic risks and estimation of critical times. In laboratory experiments, that the specimen enters the meta-instable is marked by accelerated stress release. Could we use the experimental result to identify the earthquake in natural conditions? Because the observational data from one station can only reflect the stress state beneath this station, the key problem for identification of the meta-instability is how to recognize regional stress state through observational data from many stations. In this work, we choose the evolution of the temperature field over varied deformation stages during a stick-slip event on a 5 bending fault as an example, and attempt to find the response features of the physical quantity when the fault enters the meta-instable state. We discuss the characteristics of stages for the stress build-up, stress-time process deviating from linearity before instability, meta-instability, instability, and post-instability, respectively. The result shows that the fault instability slide is a conversion process from independent activities of each fault segment to synergism activity. The instability implies completion of the synergism. The stage deviating from linearity is the onset of stress release, and it is also the onset of the synergism. At the meta-instability stages, stress release becomes dominant, while the synergism tends to finish. Therefore, the analysis of the regional overall stress state should not start from individual stations, and instead it should begin with the evolution of the whole deformation field.
