| Summary: | 碩士 === 國立雲林科技大學 === 營建工程系 === 103 === Due to a high reliability, and environmental benignity, artificial ground freezing (AGF) has been widely utilized on civil engineering projects for the construction of large open excavations and tunnels. In practice, the related thermal parameters of soil is usually estimated based on empirical rule; however, for the case of in-situ soil profile having complicated distribution or multiple-layered condition, the use of empirical rule will have its limitations. In view of the above, for reasonably and precisely simulating the transient ground temperature subjected to AGF process, a two dimensional finite element method coupling with nonlinear optimization method was proposed in this study. In this study, a series of inverse analyses based on the measured temperature from a construction site of Taipei MRT Xinzhuang Line was performed to verify the proposed inverse module. The actual monitored temperature of frozen pipe was adopted as its related boundary temperature of frozen pipe in the numerical model. The effects of measurement placements, the number of measurements, and the durations for the measured transient ground temperature on the inverse analysis results was numerically presented. Numerical results showed that compared to the simulated results using the parameters based on empirical law, the simulated temperature by using the optimized parameter set is more closed to the measured temperature. Besides, inverse analysis results showed the difference between the calculated temperature and the measured one decreased with an increase in the number of temperature measurement tube. It is also found that the monitoring duration have less effect on the above difference.
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