Nonlinear Coupled Flow-Deformation Analysis Of The Influences On Excavation Of Saturated Soft Soils

Economically advanced coastal areas of eastern China are saturated soft soilsareas, in which accidents of foundation ditch often occur. As economy of our countrydeveloping at top speed, the requirements of foundation ditch are more and more strict.The excavation of foundation ditch need to satisfy not only slope stability alsocriterion of deformation control, which ensure the surrounding buildings, subsurfacepipes and roadway be safe. However, because of the majority of design engineersthinking over this problem only basing on experience, unnecessary losses were madefrequently. To solve this problem, excavation of saturated soft soils must be knownroundly and deeply from theory.Being a classical topic in the field of soil mechanics, excavation of foundationditch in engineering practice has been made dominantly with Total Stress Analysismethods up to nowadays. In this paper, with Duncan-Chang constitutive relationshipof soils, the coupled nonlinear finite element flow-deformation-stability analysismethod is used to analyze, taking into account of the soil framework deformation andthe seepage of water excavation of foundation ditch in saturated soft soils areas. Incomparison, Effective Stress Analysis methods are more applicable. The solution tothe equation is midpoint incremental method. A Coupled Flow & DeformationBehaviors Nonlinear Finite Element Analysis of Excavation(CFEAE)program isdeveloped.In this paper, at first, the reliability of the programming is validated bycomparing the results of CFEAE with the references of the results of classicalexample. Then, various kinds of stress, displacement, potential function and porepress field are discussed. For public conduit works, the distribution regularities ofexcavation behaviors of saturated soft soils under the influence of different parametricvariations and various work conditions also are discussed in this paper. By simulatedinteracting between soils and piles, the effect of sheet piles and supporting system andthe influence of excavation of foundation ditch on foundation piles are researched.Some conclusions and recommendations for the support of excavation of saturatedsoft soils are presented.