Call number:
ZSP-201-80/10
In:
CRREL Report, 80-10
Description / Table of Contents:
A mathematical model of coupled heat and moisture flow in soils has been developed. The model includes algorithms for phase change of soil moisture and frost heave and permits several types of boundary and initial conditions. The finite element method of weighted residual (Galerkin procedure) was chosen to simulate the spatial regime and the Crank-Nicholson method was used for the time domain portion of the model. To facilitate evaluation of the model, the heat and moisture fluxes were essentially decoupled; moisture flux was then simulated accurately, as were heat flux and frost heave in a laboratory test. Comparison of the simulated and experimental data illustrates the importance of unsaturated hydraulic conductivity. It is one parameter which is difficult to measure and for which only a few laboratory test results are available. Therefore, unsaturated hydraulic conductivities calculated in the computer model may be a significant source of error in calculations of frost heave. The algorithm incorporating effects of surcharge and overburden was inconclusively evaluated. Time-dependent frost penetration and frost heave in laboratory specimens were closely simulated with the model. After 10 days of simulation, the computed frost heave was about 2.3 cm vs 2.0 cm and 2.8 cm in two tests. Frost penetration was computed as 15 cm and was measured at 12.0 cm and 12.2 cm in the two laboratory samples after 10 days.
Type of Medium:
Series available for loan
Pages:
v, 49 Seiten
,
Illustrationen
Series Statement:
CRREL Report 80-10
URL:
https://apps.dtic.mil/docs/citations/ADA084737
URL:
https://hdl.handle.net/11681/9217
Language:
English
Note:
CONTENTS
Abstract
Preface
Introduction
One-dimensional equations of simultaneous heat and moisture flux
Moisture transport
Heat transport
Phase change
Coupling effects
Frost heave algorithm
Development of computer model
Finite difference vs finite element method
Finite element formulation
Time domain solution
Evaluation of the mathematical model
Heat flux
Moisture flux
Numerical dispersion
Frost heave of homogeneous laboratory samples
Conclusions
Recommended studies to refine the model
Literature cited
Appendix A. Work plan, staffing and instrumentation requirements for correlating results oflaboratory frost susceptibility tests with field performance
Appendix B. Proposed investigation of thaw weakening of subgrade soil and granular unboundbase course
Appendix C. Derivation of finite element system matrices
Location:
AWI Archive
Branch Library:
AWI Library
