Project 1 - Deepankar Choudhury

    Objectives :

  • To evaluate various responses like displacement, stress, bending moment etc. for combined pile-raft foundation (CPRF) systems subjected to static and dynamic loads considering soil-structure interactions.
  • CPRF to be used for nuclear structures and corresponding Indian soil data will be considered for selected GHAVP soil site, basic soil and seismic data will be provided by NPCIL.
  • Foundation-soil interaction under static and dynamic loads will be analyzed numerically using finite difference approach.
  • Possibility of soil liquefaction under dynamic loading and reduction in shear strength of soil in various terms like pore pressure ratio due to dynamic loadings will be computed.
  • Interference effects between piles will be evaluated using soil-structure-soil interactions models.
  • Application of computational geomechanics with minimum computational effort/time will be obtained.
  • Compilation, comparison and validation of numerical results obtained in previous steps for various responses of CPRF subjected to static and dynamic loadings will be given.
  • Complete new design guidelines for CPRF under seismic loading considering local soil-site response study and liquefaction by taking dynamic soil-structure interaction will be proposed.

    Deliverables :

  • Free-field motion will be given by NPCIL. Based on that deconvolute to desired level and then to convolute the seismic motion at various depths of pile foundation. SHAKE and / or DEEPSOIL software will be used for getting one-dimensional seismic ground response to obtain the seismic motions at various design depths.
  • Superstructure load also now to be taken in the numerical model with actual shapes to obtain effect of superstructure size and shape on foundation system.
  • Based on obtained seismic ground response analysis, seismic design of CPRF will be started.
  • Dynamic soil-structure interaction considering soil-pile interaction, pile-pile interaction, pile-raft interaction and raft-soil interaction will be carried out using numerical finite difference based analysis.
  • Possible validation of results obtained in FLAC3D finite difference based numerical analysis will be done with available field / experimental / analytical data in literature, if any.
  • Final design steps and complete design of CPRF system for nuclear structure at the site-specific condition for a given actual problem by NPCIL will be solved.
  • Final report preparation will be done and recommendations will be provided for seismic design of CPRF considering soil-structure interactions and partial liquefaction.