Title : Evaluation of the truncated soldier pile behavior in an anchored deep excavation case study by the aid of 3d and 2d finite element analyses

Page : PP.191-202

Author(s) : Javad Jalili and Mojtaba Moosavi

Keyword : Deep excavation, soldier pile, anchored shotcrete wall, 3D numerical analysis, 2D numerical analysis

Abstract : 

In recent years many deep excavations are being conducted in urban areas of Iran, where anchored soldier piles (Berlin method) are commonly preferred as the retaining structure of the excavations. However, in some cases due to economical purposes, the soldier pile is not continued down to beneath the bottom of the excavation but is truncated somewhere between the excavation top and bottom. Such a shortened pile is called a Truncated Soldier (TS) pile in this study. Although a TS pile is believed to strengthen the local area covered by its length, it cannot provide vertical support for the retaining structure. This dominant disadvantage of the TS pile may lead to excessive settlements around the excavation. As a related case study, this paper describes the process of innovative 3D and 2D calculations utilized to improve the construction process of a 26.5 m deep excavation. The Initial excavation design contained many TS piles. Consequently, when the digging reached the depth of 18 to 24 meters, disturbing cracks showed up in some neighboring streets and structures. The excavation was stopped and a recalculation and optimization of the initial design and construction stages was done. The optimization guidelines were extracted from innovative numerical simulations. Following the guidelines, the remainder of the excavation was cleared successfully under precise monitoring. The reasonable agreement of the numerical results with those of the instrumentation at the site proved the applicability of the suggested 3D and 2D calculations in the excavation design. It is also shown that the TS piles are not reliable for deep excavations.

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