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Numerical Study of Ground Vibrations due to Pile Driving and Effect of Trench on Reduction of Amplitude of Vibrations

Khoubani, Ali | 2012

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 42765 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engineering
  6. Advisor(s): Ahmadi, Mohammad Mehdi
  7. Abstract:
  8. Ground vibration during pile driving is one the most important factors that limits usage of this kind of piles. It is of great importance to estimate the level of vibration prior to the beginning of pile driving to avoid structural damage or disturbance of building occupants. In this study, an axisymmetric finite element model that utilises an adaptive meshing algorithm has been introduced, using the commercial code ABAQUS, to simulate the full penetration of a pile from the ground surface to the desired depth by applying successive hammer impacts. The model has been verified by comparing the computed particles velocity with those measured in the field. The results indicate that the peak particle velocity at the ground surface does not occur when the pile toe is on the ground surface; as the pile penetrates into the ground, the particle velocity reaches a maximum value at a critical depth of penetration. Some sensitivity analyses have been performed to evaluate the effect of soil, pile, and hammer properties on the level of vibrations. The results show that increase in pile diameter, hammer impact force, soil-pile friction, soil friction angel, and reduction in soil elastic modulus can considerably intensify the peak particle velocity. Moreover, effectiveness of active isolation on lowering the level of vibration is investigated. According to the performed analyses, it can be concluded that increasing the depth of an open trench leads to continual reduction of the amplitude of vibration, while the width of an open trench has nearly no effect on the level of vibration. Amplitude of vibration of a point on the ground surface first decreases then increases as the distance between the open trench and the point decreases. In comparison with in-filled trench, open trench is more effective in screening of vibrations. An in-filled trench with lower elastic modulus is more successful in isolating vibrations.

  9. Keywords:
  10. Peak Particle Velocity (PPV) ; Sensitivity Analysis ; Trenche ; ABAQUS Software ; Pile Driving

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