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Analysis of Static and Dynamic Behavior of Flexible Retaining Structures Consists of Soldier Pile and Pre-Stressed Anchors by Flac-2d and 3d

Hossein Nouri, Azadeh | 2013

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 44017 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engineering
  6. Advisor(s): Haeri, Mohsen
  7. Abstract:
  8. In the recent years, in consideration with the developing of cities and increasing of population, the number of basement floors and associated depth of excavation, also, are increasing. Therefore, stabilization of the wall of these excavations is one of the most significant issues in geotechnical engineering. One of the most applicable methods in deep excavation is the use of soil anchoring by pre-stressed anchoring. This system is consisted of series of soldier piles to which, anchors, shot Crete or lagging walls, maintaining soil between piles, have been bolstered. Yet, there are lots of ambiguities about the static and the dynamic behavior of these structures. However, studies about static behavior of these structures have been enough for codes to draw up appropriate recommendations about planning them, but about the dynamic behavior of these structures, the numbers of researched subjects are not sufficient. So in this research, the static and the dynamic performance of retaining and flexible structures with pre-stressing anchors are evaluated by the use of FLAC software.
    The purpose of this modeling are recognizing of wall static performance and obtaining the amplitude of critical acceleration, peak ground acceleration and comparison of the obtained results with semi-static methods, and also studying the performance of walls under dynamic loads .The results show that the more increasing in the rigidity and depth of embedded soldier pile, anchor angle, the soil interior friction angle and the ratio of unloading to loading modulus would cause decreasing in the amount of displacements and increasing in the amplitude of critical acceleration, which is caused by the rigidity enhancing and seismic resistance of walls.
    In order to apply anchors, the best rate of angle, is 10-15 degree. Increasing the anchor length also may lead to the relative decreasing of these shifts, often it can be led to the reverse results. The results of this study state that the distribution of tension among the piles, as a phenomenon under the name of Arc Stroke, is formed in triangle shapes, and it reaches its minimum amount between the piles. Walls deformations depend mainly on the natural frequency of walls and with the closeness of these two phenomena, the Resonance occurs and the amount of the critical Amplitude of Acceleration decreases. Furthermore, the results of this research can be referred to the entering of a seismic dynamic pressure in the height of 0.4H from the wall bases. This research can be used and applied effectively for better understanding of dynamic and static behavior of retaining and flexible structures by using pre-stressed anchors
  9. Keywords:
  10. FLAC Software ; Seismic Response ; Acceleration Critical Amplitude ; Critical Seismic Coefficient ; Static Analysis ; Dynamic Analysis ; Retaining Anchored Structures

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