Modeling Inclusions in Deep Foundations Integrity Tested by Thermal Methods-PPT Presentation

PPT Presentation

Pdf Summary

The presentation uses COMSOL Multiphysics 6.2 to model heat generation and transfer in concrete deep foundations, applying hydration and soil thermal parameters to examine how thermal integrity testing responds to different defects. Simulated cases include sand layers of varying thickness, exposed reinforcement with cross-section loss, and spherical soil inclusions, with results compared against low-strain testing and crosshole sonic logging (CSL).<br /><br />The models indicate that detection depends on defect size, location, sensor placement, and measurement timing. Thin sand layers may produce weak signals or be missed by CSL, while larger inclusions are more detectable. Some modeled reinforcement defects were not detected by low-strain or CSL methods. In general, cross-sectional reductions below roughly 5% produced faint thermal signals, although thermal methods may be more sensitive than commonly used integrity tests.<br /><br />The study also compares simulations with field measurements from a shaft containing intentionally installed anomalies. The model showed sharper transitions than the field data; a thin sand layer was not clearly identified, and rock cuttings at the shaft base complicated assessment of the soft bottom. The authors note that further modeling could better represent shaft geometry and field conditions.<br /><br />Overall, numerical modeling is presented as a useful way to investigate the limits of thermal inclusion detection. The findings also highlight the need for the profession to determine what degree of reduction or defect is acceptable while still meeting foundation performance requirements.

Keywords

COMSOL Multiphysics

concrete deep foundations

heat transfer

hydration heat

thermal integrity testing

defect detection

sand layer

reinforcement loss

crosshole sonic logging

low-strain testing