Filters

2014 - 20154

Settings

Now showing1 - 4 of 4
  • Some of the metrics are blocked by your 
    consent settings
    Item type:Publication, Access status: without files ,
    Large displacements and fluidization of sand due to seepage
    (2015-12)
    Grabe, Jürgen
    ;
    Stefanova, Bozhana
    Seepage inside the soil body is able to cause distortion of the soil skeleton especially at large seepage velocities and/or pressure gradients. In this way not only displacements can occur but also internal erosion or even fluidization of the seabed. This paper presents the numerical analysis of two basic test cases of seepage through the soil body. The aim is to determine the displacements due to the seepage as well as to capture the potential soil liquefaction. The meshless method Smoothed Particle Hydrodynamics (SPH) is used for the numerical analysis. The soil is simulated as a two phase medium and the hypoplastic constitutive model is employed for the calculation of effective stress.
    Publicationtype: Conference Paper
      104
  • Some of the metrics are blocked by your 
    consent settings
    Item type:Publication, Access status: without files ,
    Numerical modeling of saturated soils based on smoothed particle hydrodynamics (SPH): Part 2: Coupled analysis
    (2015-09-01)
    Grabe, Jürgen
    ;
    Bozhana, Stefanova
    In the first part of this paper the meshless numerical method smoothed particle hydrodynamics (SPH) was introduced, and its application for seepage analysis was presented. In this second part the method is extended to truly coupled analysis using a two-phase model for saturated soils. In contrast to the simulations in the first part of the paper the soil is also subjected to displacements. A hypoplastic constitutive model is applied to the soil, considering a liquefaction threshold for the case of very low effective stress or tension. The interaction between the two phases - water and soil - is presented for the case of laminar and turbulent flow. Various approaches for the evaluation of the interaction coefficients are introduced and evaluated. Test cases for verification and application of the SPH model are presented and discussed.
    Publicationtype: Journal Article
      45
  • Some of the metrics are blocked by your 
    consent settings
    Item type:Publication, Access status: without files ,
    Numerical modeling of the flow and seabed erosion around a pipeline using smoothed particle hydrodynamics (SPH)
    (2015-05)
    Bozhana, Stefanova
    ;
    Grabe, Jürgen
    Pipelines placed on the seabed are subjected to a range of hydrodynamic forces due to currents, waves and tidal events.The seabed is often disturbed by the complex flowconditions so that sediment transport and erosion can be caused. Recent experiments, conducted at the University ofWestern Australia in the experimental facility O-tube, have shown that the scour around the pipeline is related to the flow velocity and conditions as well as to the pipeline embedment. Furthermore, the occurrence of scour is able to cause displacements of the pipeline. This paper presents numerical analysis based on the aforementioned experiments. It focuses on the flow conditions and the loading of the pipeline and the seabed in order to summarize the factor of influence for the development of scour and erosion. For this purpose the meshless numerical method Smoothed Particle Hydrodynamics (SPH) is used. A novel application using a two phase model and the hypoplastic constitutive model for soil is presented.
    Publicationtype: Conference Paper
      72
  • Some of the metrics are blocked by your 
    consent settings
    Item type:Publication, Access status: without files ,
    SPH model of water jet erosion in granular soils with a boundary layer of liquefied soil
    (2014-06)
    Bozhana, Stefanova
    ;
    Grabe, Jürgen
    The interaction between fluids and soil is important to a wide range of geotechnical problems. Especially when considering high velocity impacts, such as jet grouting, the interaction between both phases is quite complex, due to the dynamic and turbulent processes occurring. This paper describes a series of experiments concerning high velocity injection into soil, which were conducted in 2005. The experiments are used as a base for the numerical modeling of the process, for which the smoothed particle hydrodynamics (SPH) was applied. SPH is a meshfree method, which was originally employed in the late 1970's for astrophysical calculations. Nowadays, it is being used in a vast range of research domains including fluid and solid mechanics, hydrodynamics and also coastal and geotechnical engineering. SPH uses particles to describe materials in Lagrangian point of view. It is able to deal with large deformations and dynamic processes. Our goal is to provide an innovative application of SPH for the simulation of the interaction between water and soil in the framework of multiphase models. The analysis is supposed to give information on the penetrations process of a high velocity water jet into the soil as well as the penetration depth and the mechanism of soil liquefaction during jet grouting. © 2015 Taylor & Francis Group.
    Publicationtype: Conference Paper
      95