Recognition of PCM in soil using semantic segmentation model and numerical simulation.

Phase change material (PCM) mixed in soil can effectively adjust the subgrade temperature. In order to analyze the temperature field change of soil containing PCM more accurately from the microscopic point of view, it is a key problem to construct a refined geometric model. This paper scans the fracture plane of soil containing PCM through the stereoscopic microscope and prepares the label image corresponding to the sample image. Then a U-Net semantic segmentation model is established, which can accurately recognize PCM area and soil area. Finally, a geometric model of soil containing PCM that is consistent with reality is established, and its heat transfer characteristics are analyzed by finite element method. The accuracy evaluation of the segmentation model and the visualization of the recognition results show that the evaluation indexes of U-Net are the best. P, R, F1, and MIoU of U-Net are 0.889, 0.918, 0.903, and 0.901, respectively. The refined model established in this paper can not only observe the overall temperature regulation effect of the material but also accurately describe the internal temperature distribution details of soil containing PCM during heat transfer. Through numerical simulation, it is found that the maximum temperature of mixture decreases by 1.6 °C and the minimum temperature of mixture increases by 2.3 °C. [ABSTRACT FROM AUTHOR]