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Norbert Kömle, Günter Kargl Space Research Institute, Austrian Academy of Sciences Graz, Austria

MUPUS Progress Meeting Graz 24-25 October 2013. A pile driving model applied to the hammering insertion of the MUPUS penetrator Preliminary results. Norbert Kömle, Günter Kargl Space Research Institute, Austrian Academy of Sciences Graz, Austria. Items to be considered.

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Norbert Kömle, Günter Kargl Space Research Institute, Austrian Academy of Sciences Graz, Austria

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  1. MUPUS Progress Meeting Graz 24-25 October 2013 A pile driving model applied to the hammering insertion of the MUPUS penetratorPreliminary results Norbert Kömle, Günter Kargl Space Research Institute, Austrian Academy of Sciences Graz, Austria

  2. Items to be considered • Piledriving in geotechnical engineering • Scaling to MUPUS-PEN dimensions and mass • Modelling method: • Represent pile and hammer by springs and weights • Numerical solution of the 1D wave equation • Compute solutions for various configurations (MUPUS-PEN, mole, etc.) for 1 stroke! • Make parameter studies by computing solutions for different values of hammer impact velocity, gravity, and probe and soil material-parameters

  3. Pile driving models (dynamic) Key references: Smith (1951): Pile driving impact Lovery et al. (1969): Pile driving analysis – State of the art Salgado and Zhang (2012): Use of pile driving analysis for assessment of axial load capacity profiles A piledrivenintosoilby subsequent impactsby a ramfromthetopsidecanbedescribedby a sequenceofmassesconnectedbysprings. The basicequationtobesolvedistheone-dimensional waveequation.

  4. Pile driving models Model adapted to the „mole“ configuration: Hollow tube driven by the impact of an interior ram weight Standard model used for driving a pile from top side Ref.:Smith E.A.L. (1962): Pile-driving aanalysis by the wave equation. Transactions ASCE 127, Part I, pp- 1145-1183.

  5. PEN Parameters

  6. Soil Parameters Soil shear module: G_soil=E_soil/(2*(1+nu_soil)) Soil quake at tip: Q_soil=(1+nu_soil)/(2*E_soil)*yield_soil*rad_tube Soil quake for side friction: Q_tube=shear_soiltube/G_soil*rad_tube*log(rad_disturbed/rad_tube)

  7. Results (1): time evolution of different model variables durng one MUPUS hammer stroke

  8. Results (2): time evolution of different model variables during one MUPUS hammer stroke for small gravity

  9. Results (3): Soil displacement for different power settings of the MUPUS hammer

  10. Further Studies • Influence of coefficient of restitution < 1 (Titan on Titan ?) on the solutions • Effect of different hammer modes (impact velocities) on penetration per stroke • Influence of soil parameters (cohesion, angle of internal friction, shear strength) on penetration per stroke • Include the casing of the hammer and its mass into the model A model of this type also allows to analyse the tensional an compressional stress along the PEN-tube during a stroke.

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