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Publikācija: Dynamical Effects in Process of Piles Vibrodriving

Publication Type Publications in RTU scientific journal
Funding for basic activity Unknown
Defending: ,
Publication language English (en)
Title in original language Dynamical Effects in Process of Piles Vibrodriving
Field of research 2. Engineering and technology
Sub-field of research 2.5 Materials engineering
Authors Svetlana Polukoshko
Olga Kononova
Svetlana Sokolova
Keywords vibration, parametric load, dynamical stability, friction, liquefaction
Abstract Vibration driving of elements into a soil is a complex mechanical process, accompanied with such phenomena, as a changing of structure of surrounding the driving element soil, liquefaction of them, the decreasing of friction forces between soil and surface of the driving element. A vibration method is used for driving of elements with the comparatively small cross section area: metallic sheet piles and pipes; length of sinking elements is not limited. When periodically changing axial force is acting on the driving elements there is possibility of loss of dynamical stability of element because of parametric resonance. Such possibility appears when motion of element bottom end is obstructed by the layers of very hard soil (for example, rocky) or because of densification of the liquefied sandy soil after technological pause in vibrodriving. In this work it is suggested to check up the parameters of vibrators using the simulation of pile driving process and examination of pile dynamical stability. The plastic model of shaft and toe resistance of soils during vibrodriving is developed taking into account the change of properties of soils on the depth, equation of motion of pile in soil is derived and solved numerically. The analysis of numerical solution shows the possibility of element driving to required depth by one vibrator with given performance figures, or the necessity of additional static set-on-weight, additional vibrator or changing of vibrator. The possibility of origination of dynamical instability and condition of resonance is examined on the models of pile as a perfectly solid and as a flexible beam. Possibility of dynamic stability loose on the higher mode of vibrations is proved for the driving elements from the often applied metallic rolled sections, examined as flexible beams.
Reference Polukoshko, S., Kononova, O., Sokolova, S. Dynamical Effects in Process of Piles Vibrodriving. Mechanics. Vol.33, 2010, pp.109-116. ISSN 1407-8015.
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