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| Titel |
An Equipment to Measure the Freezing Point of Soils under Higher Pressure |
| VerfasserIn |
Dayan Wang, Hui Guan, Zhi Wen, Wei Ma |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250087288
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| Publikation (Nr.) |
 EGU/EGU2014-1320.pdf |
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| Zusammenfassung |
| Soil freezing point is the highest temperature at which ice can be presented in the
system and soil can be referred to as frozen. The freezing temperature of soil is an
important parameter for solving many practical problems in civil engineering, such as
evaluation of soil freezing depth, prediction of soil heaving, force of soil suction, etc.
However, as the freezing temperature is always affected by many factors like soil
particle size, mineral composition, water content and the external pressure endured
by soils, to measure soil freezing point is a rather difficult task until now, not to
mention the soil suffering higher pressure. But recently, with the artificial freezing
technology widely used in the excavation of deep underground space, the frozen
wall thickness is a key factor to impact the security and stability of deep frozen
wall. To determine the freeze wall thickness, the location of the freezing front must
be determined firstly, which will deal with the determination of the soil freezing
temperature. So how to measure the freezing temperature of soil suffering higher
pressure is an important problem to be solved. This paper will introduce an equipment
which was developed lately by State Key Laboratory of Frozen Soil Engineering
to measure the freezing-point of soils under higher pressure. The equipment is
consisted of cooling and keeping temperature system, temperature sensor and data
collection system. By cooling and keeping temperature system, not only can we
make the higher pressure soil sample’s temperature drop to a discretionary minus
temperature, but also keep it and reduce the heat exchange of soil sample with the outside.
The temperature sensor is the key part to our measurement, which is featured by
high precision and high sensitivity, what is more important is that the temperature
sensor can work in a higher pressure condition. Moreover, the major benefit of this
equipment is that the soil specimen’s loads can be loaded by any microcomputer control
electron universal testing machines. All of above mentioned advantages of this
equipment ensures one to catch up the moment soil turns from the thawed state into ice
and enable one to determine the freezing point experimentally by recording the
temperature–time history (cooling curve) at particular points within the sample
used for analysis. Therefore, this equipment has excellent characteristics such as
compact construction, convenient operation, high reliability and the measuring
accuracy.
The authors would like to thank the following agents for their financial supports:
the National Natural Science Foundation (No.41071048),Hundred Talent Young
Scientists program of the Chinese Academy of Sciences granted to Dr. Zhi Wen. |
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