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Dilatancy of soils as a factor influencing the bearing capacity and load - displacement response of deep foundations
Dvořák, Tomáš ; Koudela, Pavel (referee) ; Chalmovský, Juraj (advisor)
In theory of soil mechanic the dilatancy has a significant influence, which may fundamentally affect bearing capacity and behavior of geotechnical constructions. In the past it was difficult to include influence of dilatancy directly in to calculation, but now with development of numerical analysis and growth of computer performance it is much easier. In this work there are introduced fundamental dilatancy models and phenomen called constraint dilatancy, which causes stress changes in soil or at soil – construction interface. This stress changes may lead to higher bearing capacity. In this work, the effect of constraint dilatancy is focused on bored pile’s shaft. Next target of this work is including dilatancy to calculation. By empirical methods, by direct application with theory of cylindrical cavity expansion and last by numerical calculation with finite element method in software Plaxis with using the Hardening Soil model.
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Prediction of load-displacement behaviour of large diameter piles using the finite element method
Dvořák, Tomáš ; Miča, Lumír (referee) ; Chalmovský, Juraj (advisor)
The master thesis deals with the inverse analysis of instrumented load tests of bored piles in cohesionless and cohesive soils. Evaluations of the detailed monitoring are compared with the results of inverse analyses. Inverse analyses are preformed using the finite element method with an advanced material model considering the higher stiffness within very small strains in PLAXIS and alternatively using the load-transfer method in PMpLTO. The difference of pile-soil interaction in different soil types is discussed and the difference in the process of shaft friction mobilization is also evaluated. In cohesionless soils values of shaft friction are many times higher due to the increment of radial stress which is caused by effect of constraint dilatancy in shear zone at pile-soil interface.
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Dilatancy of soils as a factor influencing the bearing capacity and load - displacement response of deep foundations
Dvořák, Tomáš ; Koudela, Pavel (referee) ; Chalmovský, Juraj (advisor)
In theory of soil mechanic the dilatancy has a significant influence, which may fundamentally affect bearing capacity and behavior of geotechnical constructions. In the past it was difficult to include influence of dilatancy directly in to calculation, but now with development of numerical analysis and growth of computer performance it is much easier. In this work there are introduced fundamental dilatancy models and phenomen called constraint dilatancy, which causes stress changes in soil or at soil – construction interface. This stress changes may lead to higher bearing capacity. In this work, the effect of constraint dilatancy is focused on bored pile’s shaft. Next target of this work is including dilatancy to calculation. By empirical methods, by direct application with theory of cylindrical cavity expansion and last by numerical calculation with finite element method in software Plaxis with using the Hardening Soil model.
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