Geotechnical support for the construction of a unique building through the observational design method

Introduction. In geotechnical design practice, it is common to find objects whose underground structure behavior is difficult to predict based on calculation or experimental work. Such cases permit the use of the observational method allowing for design adjustments during construction according to the results of geotechnical monitoring. The paper describes a practical example of applying the observational method at the construction site of a unique building in the center of Moscow.
Aim: to evaluate the actual performance of underground structures and, if necessary, to develop and apply corrective measures within the observational design method using the results of geotechnical monitoring.
The subject matter of the study is a unique unfinished building with a five-story underground part exhibiting an uncertain mechanical performance of the foundation at the interface with the retaining wall of the foundation pit due to the long-term suspension of the construction site. The behavior of the underground structures, including their interaction with the bearing soil and the slurry wall, was controlled using a comprehensive system of geotechnical monitoring implemented at the site.
Results. The adopted design solutions and the use of corrective actions within the observational design method reduced the effect of existing adverse geotechnical conditions at the site in question, specifically increasing the stiffness of the underground part and minimizing the settlement difference between the central and edge parts of the foundation slab.
Conclusions. It is established that geotechnical monitoring provides a means to evaluate the behavior of the building exhibiting an uncertain mechanical performance of structures within the observational design method.

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