MITIGATION OF SEISMIC LIQUEFACTION IN THE FOUNDATION SOIL OF EXISTING STRUCTURES VIA PORE FLUID ENRICHMENT WITH ENVIRONMENTALLY SAFE NANO-PARTICLES

Abstract: 

At developed sites, liquefaction mitigation techniques are either difficult or impossible (e.g. vibroreplacement) to implement. In such cases, underpinning, high viscosity grouting or perforated drains are often prescribed, which cannot mitigate liquefaction under the whole structure and may create structural problems (e.g. footing heave). Also, operation is obstructed during works and the improvement of large areas is costly.

AIM: An alternative technique without these drawbacks is passive stabilization, i.e. the slow injection of a stabilizer-enriched pore fluid with time-increasing viscosity at the upgradient side of a developed site followed by delivery under the structure via groundwater flow. Colloidal silica and clay nano-particle mixtures have been proposed as stabilizers, but the technique is not yet applicable in practice. This proposal aims to make passive stabilization a theoretically sound, fail-safe and practical technique for liquefaction mitigation.

WORK-PACKAGES:

  1. Literature: Materials-Procedures,
  2. Tests: Rheology, permeation, unconfined compression,
  3. Analyses: stabilizer delivery via groundwater flow,
  4. Tests: Monotonic response,
  5. Tests: Cyclic/Dynamic response,
  6. Constitutive modeling,
  7. Model(s) implementation in FE/FD code(s),
  8. Analyses: Seismic response, design spectra (FE/FD)-Micromechanical response (DEM),
  9. Springs-dashpot,
  10. Design charts-specifications,
  11. Field test,
  12. Coordination.

EXPECTED RESULTS:

  • Design methodology (10) for the optimal stabilizer (1), based on lab data (2,4,5), constitutive modeling (6) and numerical analyses (3,7,8), following comprehension of the micromechanical stabilization mechanism (2,8),
  • Specifications (10) for quality control and assurance (e.g. viscosity control), cost, durability and environmental safety, complemented with design spectra (8) and springs-dashpots (9) for the dynamic analysis of the retrofitted structure. Effectiveness & applicability will be verified insitu (11).

Project info

Acronym:
NANO-LIQ
Coordinating Institution:
University of Thessaly
Scientific Coordinator:
Papadimitriou Achilleas
Research Team 2 Leader:
Dakoulas Panagiotis
Research Team 3 Leader:
Tika-Vasilikou Theodora
Research Team 4 Leader:
Bouckovalas George

Stats

I.D.:
292
Mis:
375618
Duration (months):
43
Budget:
600 000.00
Diavgeia:
ΑΔΑ: Β49Υ9-ΕΓΞ

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