University: Charles University Supervisor: David Mašín
Hypoplastic model for unsaturated expansive clays has recently been implemented into an inhouse finite element code SIFEL developed at Czech Technical University. It has been used successfully in simulating behaviour of bentonite buffer in planned nuclear waste repositories.Recently a European framework funded project BEACON has been setup to investigate the process of homogenization of bentonite blocks and pellets to guarantee adequate sealing properties of the buffer. In the proposed project it is planned to both investigate the behaviour of the buffer in laboratory experiments and to numerically model its behaviour. Laboratory testing will be performed on newly acquired THM unsaturated oedometric apparatus, enabling to perform tests up to 150 °C. Numerical modelling will be done using SIFEL finite element code with hypoplastic constitutive model. The PhD project will thus stimulate both laboratory and numerical skills of the applicant, while he will have a freedom to decide specific orientation of the project depending on his/her interests.
I have just returned to Springer proofs of my new book “Modelling of Soil Behaviour with Hypoplasticity – Another Approach to Soil Constitutive Modelling“. It will probably still take few weeks before the book is published, it is however already now available for preorders at: https://www.springer.com/us/book/9783030039752
In Part I of the book, I first describe principles of hypoplasticity using simple 1D and 2D versions, which are straightforward to follow. This is demonstrating how two primary properties of hypoplasticity – non-linearity and asymptotic behaviour – are incorporated in the models. This demonstration is accompanied with explanation of experimental evidence on soil behaviour and with a brief overview of other possible modelling approaches. Then, full tensorial formulation of hypoplastic models is described and explained. In Part II, two specific models are introduced: model for sand and model for clay. They are described in detail and it is explained how to properly calibrate material parameters. Finally, advanced extensions of the models are covered, aimed to predict the effects of small strain stiffness and cyclic loading effects, effects of structure, rate effects, stiffness anisotropy, partial saturation and thermal effects.