ICSE 6 – 6 th International Conference on Scour and Erosion, Paris Aug. 27-31 2012 Water-Soil Interaction Simulation using Smoothed Particle Hydrodynamics Bozhana STEFANOVA, Karlotta SEITZ, Julian BUBEL, Jürgen GRABE Hamburg University of Technology Institute of Geotechnical Engineering and Construction Management TUHH Water –Soil Interaction Simulation using SPH - Stefanova, Seitz, Bubel, Grabe 1
ICSE 6 – 6 th International Conference on Scour and Erosion, Paris Aug. 27-31 2012 Introduction • Gravity base • Jet grouting: foundation for an – used since the 1970´s offshore wind energy – method of ground converter: improvement and stabilization – hollow structures – high presure streams to made of concrete break up the soil – manufactured onshore and transported to the construction site – lowered into a prepared foundation pit TUHH Water –Soil Interaction Simulation using SPH - Stefanova, Seitz, Bubel, Grabe 2
ICSE 6 – 6 th International Conference on Scour and Erosion, Paris Aug. 27-31 2012 Introduction • Gravity base • Jet grouting: foundation for an – used since the 1970´s offshore wind energy – method of ground converter: improvement and stabilization – hollow structures – high presure streams to made of concrete break up the soil – manufactured onshore and transported to the construction site interaction between – lowered into a prepared foundation fluid and soil pit TUHH Water –Soil Interaction Simulation using SPH - Stefanova, Seitz, Bubel, Grabe 3
ICSE 6 – 6 th International Conference on Scour and Erosion, Paris Aug. 27-31 2012 Lowering of a gravity base foundation (GBF) water flow underneath the foundation is induced: → flow in the voids of the soil → erosion TUHH Water –Soil Interaction Simulation using SPH - Stefanova, Seitz, Bubel, Grabe 4
ICSE 6 – 6 th International Conference on Scour and Erosion, Paris Aug. 27-31 2012 Soil interaction with a fluid jet • high velocity and pressure • different stages of interaction • reduction of effective stress in the soil TUHH Water –Soil Interaction Simulation using SPH - Stefanova, Seitz, Bubel, Grabe 5
ICSE 6 – 6 th International Conference on Scour and Erosion, Paris Aug. 27-31 2012 Smoothed Particle Hydrodynamics (SPH) • meshfree method • uses particles that have the properties of the material • originally applied in the 1970`s in the astrophysics • nowadays used for different physical, hydrodynamic and also geotechnical calculations • approximation for each particle using its neighbors (fig. after Colagrossi, 2003) TUHH Water –Soil Interaction Simulation using SPH - Stefanova, Seitz, Bubel, Grabe 6
ICSE 6 – 6 th International Conference on Scour and Erosion, Paris Aug. 27-31 2012 Conservation equations in SPH mass conservation momentum conservation equation of state TUHH Water –Soil Interaction Simulation using SPH - Stefanova, Seitz, Bubel, Grabe 7
ICSE 6 – 6 th International Conference on Scour and Erosion, Paris Aug. 27-31 2012 Implementation in SPH • soil as a viscous fluid, using Gadget H 2 O by C. Ulrich & T. Rung – viscosity μ as function of the angle of friction φ , cohesion c , pressure p and deviatoric strain rate ė : – useful approach to study the applicability and feasibility of the models – for further geotechnical applications: more sophisticated treatment of soil needed TUHH Water –Soil Interaction Simulation using SPH - Stefanova, Seitz, Bubel, Grabe 8
ICSE 6 – 6 th International Conference on Scour and Erosion, Paris Aug. 27-31 2012 Simulation of the lowering of a gravity base foundation Model setup STRABAG Gravity Base (Weber, 2010) TUHH Water –Soil Interaction Simulation using SPH - Stefanova, Seitz, Bubel, Grabe 9
ICSE 6 – 6 th International Conference on Scour and Erosion, Paris Aug. 27-31 2012 Results for lowering of a gravity base foundation 5 s 15 s initial configuration velocity magnitude [m/s] TUHH Water –Soil Interaction Simulation using SPH - Stefanova, Seitz, Bubel, Grabe 10
ICSE 6 – 6 th International Conference on Scour and Erosion, Paris Aug. 27-31 2012 Results for jet grouting particles velocities 0.015s 0.03s [m/s] TUHH Water –Soil Interaction Simulation using SPH - Stefanova, Seitz, Bubel, Grabe 11
ICSE 6 – 6 th International Conference on Scour and Erosion, Paris Aug. 27-31 2012 Results for jet grouting particles velocities 0.015s 0.03s [m/s] TUHH Water –Soil Interaction Simulation using SPH - Stefanova, Seitz, Bubel, Grabe 12
ICSE 6 – 6 th International Conference on Scour and Erosion, Paris Aug. 27-31 2012 Conclusions & outlook • soil-water interaction for two geotechnical problems was analyzed • promising results • future goals – two-phase-model in order to describe the soil-fluid- interaction – test cases for numerical analysis & variation of parameters – calibration and validation of the simulation results TUHH Water –Soil Interaction Simulation using SPH - Stefanova, Seitz, Bubel, Grabe 13
ICSE 6 – 6 th International Conference on Scour and Erosion, Paris Aug. 27-31 2012 T HANK Y OU FOR Y OUR ATTENTION ! TUHH Water –Soil Interaction Simulation using SPH - Stefanova, Seitz, Bubel, Grabe 14
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