ABSTRACT

Deep excavations in soft ground often require additional stabilization through ground improvement (GI). Some of the common methods to improve the ground are Jet Grouting Piles (JGP), Deep Soil Mixing (DSM) or Wet Speed Mixing (WSM). JGP, DSM and WSM are achieved by mixing the soil with cement and water, generating a structure that performs well under compression forces but not under tension forces. These ground improvement blocks provide larger passive resistance and thereby reduce wall displacements. For Ground Improvement properties different design codes along different regions and countries define different approaches and nowadays there is not a unique strategy when it comes to define the strength and stiffness properties of GI.

This paper focuses on the selection of appropriate ground improvement parameters during design phase. The discussion is supported by a monitored excavation of a TBM shaft and a back analysis using FEM 2D models.