Consolidation Analysis Of Footings Embedded In A Finite Stratum

The degree of consolidation settlement U is usually calculated either by the ordinary Terzaghi one-dimensional consolidation theory or by the Biot's coupled theory of consolidation.The Biot's theory of consolidation will produce a better result but relatively few solutions have been obtained even with the modern developments of numerical methods because of the complexity of the equations.To the authors' knowledge,solution charts and/or tables illustrating the average degree of consolidation settlement involving embedded foundations have not appeared heretofore.This obviously hinders the frequent use of Biot's theory for practical foundation problems.This paper uses the finite element method to investigate the consolidation behavior of circular and strip footings embedded in a finite stratum based on Biot's consolidation theory.The calculation was carried out using a well-known finite element package,ABAQUS.The influences of three factors:(1) the ratio of buried depth to the thickness of the stratum;(2) the ratio of footing width to the thickness of the stratum;and(3) the Poisson's ratio of the soil skeleton on the average degree of consolidation settlement are examined.Based on the results of analysis,new normalized time factors are suggested.It is shown in the paper that the average degree of consolidation exhibits very good normalized behavior using the time factors.The author also present solution charts for determining the average degree of consolidation settlement of circular and strip footings embedded in a finite stratum.The charts can provide engineers with a quick answer to the design issues.The maximum error caused by using the solution charts is within 3%.