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Study On Torsional Dynamic Interactions Of Elastic Pile And Poroelastic Medium

Posted on:2007-08-27Degree:DoctorType:Dissertation
Country:ChinaCandidate:G ChenFull Text:PDF
GTID:1102360185481056Subject:Geotechnical engineering
Abstract/Summary:PDF Full Text Request
Basing on the stress-strain relationships of poroelastic medium and the governing equations of pile, considering the boundary conditions between soil and pile, the torsional dynamic interactions of saturated soil and buried elastic cylindrical pile.To study the steady-state response of pile buried in saturated soil, a "fictitious" pile is introduced and is define as: the embedding medium was extended to half-space. A fictitious pile was introduced as a reinforcement through the region of the cylindrical pile. The governing equations of extended foundation are resolved through the application of Hankel integral transforms. By using the boundary conditions, the influence functions of stress and displacement are obtained corresponding to a torsional load applied in the interior of a poroelastic half-space. The buried elastic is governed by one-dimension wave equation. Combining the displacement compatibility condition between the pile and the soil, the pile governing equation is deduced to a Fredholm's integral equation of the second kind about the bar-force of the fictitious pile. The integral equation can be resolved by numerical quadrature, and the torque of the fictitious pile can be determined. The further data are calculated to illustrate the dynamic characteristics of the elastic pile. The thesis considers the elastic pile in transversely isotropic saturated soil and layered saturated soil too.The transient response of pile buried in poroelastic medium is studied by thin layer chromatography. The pile-soil system is divided into adequate thin layers, and the gradient of shear stress τθz of soil in the vertical direction is neglected. Laplace transform is used to solve the governing equations of soil layer and pile segment respectively. Considering the mixed boundary-value conditions at the interface of pile and soil, expression is derived to describe the relationship between the inner force and the displacement of the pile segment. Then the expressions of all pile segments are integrated to form the stiffness matrix equation of pile. The pile displacement in time domain is calculated by numerical method. In addition, the soil characters of transversely isotropic and viscoelasticity are also considered in this paper.
Keywords/Search Tags:poroelastic soil, half-space, elastic pile, steady-state response, transient response, dynamic interaction
PDF Full Text Request
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