Improvement of the test Method for the Thermal Integrity of Cast-in-place Pile Tip: Optimizing The Layout of Temperature Measuring Points
Zhiguo Ma, Chenjin Shi, Yuan Hou, Chao Xue, Minghao Sun and Yong Zeng
Transactions on Machine Design, Vol. 12, No. 1, 2024.
DOI: https://doi.org/10.6025/tmd/2024/12/1/1-19
Link: https://www.dline.info/tmd/fulltext/v12n1/tmdv12n1_1.pdf
Abstract:
Due to the nature of underground structures, detecting defects in pile foundations is very difficult. Many methods for detecting such defects are currently in use, with various advantages and disadvantages. A new defect detection method has been proposedâ€”thermal integrity detection. When an abnormal concrete temperature occurs, this abnormality is attributed to a defect within the concrete. When the temperature is elevated, it is attributed to bulging; when the temperature is depressed, it is attributed to necking, mud entrapment, or hollowing. Using finite element analysis can make the identification of defects quantifiable, but the study of concrete defects in pile foundations becomes complicated due to undesirable choice of temperature measurement point locations, reducing the efficiency and accuracy of finite element inverse analysis. Based on previous research, the location of temperature measurement points is optimized in this work. First, the effect of the change of reinforcement position on the concrete temperature field is studied, and it is confirmed that the change of reinforcement position affects only the location of the measurement points, not the concrete temperature field itself. Then measurement points on the concrete surface are selected for finite element inverse analysis of the pile temperature field and the results are compared with measurements in the field. The new measurement points can avoid irrelevant factors in the finite element inverse analysis of the pile foundation temperature field. The complexity of the finite element inverse analysis is greatly reduced, and the accuracy of defect location and size identification is improved.