Displacement based design of multi level anchored deep excavations

Abstract

Braced deep excavations are getting widespread in parallel to the increase in the need to use underground spaces for infrastructures and tall buildings which make them an essential part of geotechnical engineering practice. Braced support system movements shall be small enough to ensure remain within acceptable limits. The limits for the elastic displacement of the vertical support member (e.g., pile wall), are generally recommended either for support systems with strut elements or cantilever walls. However, there is no common specification or guide to assess the permissibility of displacements caused by deep excavations with multi‐level anchors. This paper presents an example study for a deep excavation project supported with multilevel anchors in a clayey soil in Istanbul where Mobilized Strength Design (MSD) method is discussed and a new approach is proposed regarding the limit of the horizontal elastic deflection value of the vertical wall with multi‐level anchors, based on a joint evaluation of the performed finite element study and MSD method.