Resumo

PINEDA-JAIMES, Jorge Arturo  e  LARRANAGA-RUBIO, Sherley Catheryne. Base Heave Stability in Circular Excavations with Diaphragm Walls in Overconsolidated Clays: Parametric Analysis and Simplified Method. TecnoL. [online]. 2025, vol.28, n.62, e205.  Epub 12-Ago-2025. ISSN 0123-7799.

Trenchless methods have recently been implemented in Bogotá's sanitation works to install collectors over 3 m in diameter. These use deep circular shafts supported by cast-in-place diaphragm walls and concrete rings for launching and receiving tunneling equipment. Axisymmetric conditions require precise determination of wall embedment depth and verification of bottom failure stability in superficially overconsolidated clays. This article evaluates the safety factor against base heave failure through parametric analysis and proposes a simplified evaluation method. The methodology consisted of performing numerical simulations using finite elements, considering variations in the excavation diameter, its free height, and the embedment depth of the diaphragm walls in a clay profile from southwestern Bogotá, characterized on the basis of an in-situ CPTU test. The results indicated that the safety factor depends mainly on the geometric properties of the excavation, the depth of the embedment of the containment system, and the undrained shear strength of the clay beneath the bottom of the excavation. Finally, based on the results of parametric modeling, it is concluded that the effect of the surficial overconsolidation on the safety factor can be expressed in a semi-empirical equation through an adjustment coefficient (α), being more significant in excavations with a reduced diameter. These results contribute to improving the evaluation of excavation stability and optimizing construction strategies, promoting safer, more sustainable, and more resilient solutions in the design of underground works.

Palavras-chave : Overconsolidated clays; circular excavations; bottom failure; safety factor; diaphragm walls.

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