Modeling the natural freezeback of piles using COMSOL Multiphysics®

Abstract

Slurried pile foundations installed in predrilled holes are one of the most common foundations for building major structures on permafrost. This installation method relies on the cold permafrost to freeze the backfilled slurry around the piles to provide the strength required to support loads of a structure. Nearly all evaluations of freezeback time to date stems from the work of Frederick Crory presented to the First International Conference on Permafrost in 1963 and published in 1966. Crory never published field data but he provided an equation to determine freezeback time. This work was later expanded upon by G.H. Johnston in 1981 however Johnston gives no explanation for how or why he varied from what Crory had done. The purpose of this research is to check the results predicted by both Crory and Johnston with a contemporary computer modeling using COMSOL ® Multiphysics. Due to the advancement in technology and the power of COMSOL as a program more variables and situations will be able to be examined than what was available to Crory or Johnston at the times of their publications. This will be the first research in over 50 years to revise the work first published by Crory and show that his equation produces results that are significantly shorter than what the model calculates.