Photoelectric test system and method for in-situ frozen soil ice water component identification and dynamic tracing

Abstract

The invention discloses an in-situ frozen soil ice water component identification and dynamic tracing photoelectric test system and method. The test system comprises a photoelectric sensing test assembly, a data demodulation analysis system and a self-contained pulse power supply control system. The photoelectric sensing test assembly comprises a plurality of photoelectric sensing test units which are connected in series; the photoelectric sensing test unit comprises a variable-temperature ultra-weak fiber bragg grating sensing optical cable and a plurality of frequency domain reflection probes, and the frequency domain reflection probes correspond to the variable-temperature ultra-weak fiber bragg grating sensing optical cable measuring points. Through ultra-weak fiber grating temperature sensing and frequency domain reflection technologies, based on the pulse temperature change and multiphase heat dissipation principle, and through the relation between the frozen soil temperature response value and the soil body heat conductivity coefficient, the moisture content and the ice content, ice water components in the in-situ frozen soil are identified, and moisture field parameters are accurately measured; the frozen soil ice and water component identification and dynamic tracing are realized, the problem that parameters are difficult to measure due to unstable frozen soil properties is solved, and the method has the advantages of small disturbance, distribution, real-time performance and automation.

Description

technical field [0001] The invention relates to a device and method for measuring the moisture content and ice content of frozen soil in geotechnical engineering and geological engineering, in particular to a photoelectric testing system and method for in-situ frozen soil ice water component identification and dynamic tracing. Background technique [0002] Frozen soil is a multiphase complex system composed of soil particles, ice, unfrozen water, and gas. Its characteristics are related to various basic physical properties such as soil texture, density, and moisture content. Among them, soil temperature and soil moisture field parameters with water content and ice content as basic parameters are important information for theoretical research and engineering practice of hydro-thermal-mechanical coupling in frozen soil regions. However, due to the extremely strong temperature sensitivity of frozen soil, the temperature, moisture content and ice content of in situ frozen soil a...

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Problems solved by technology

However, the bottleneck of this technology mainly lies in the fact that the active heating method of the optical cable has the problems of too long heating time, great interference to the soil moisture field, and the inability to effectively realize the identification of ice and water groups under negative temperature conditions, resulting in excessive test errors , hindering the application of the technology

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