Development of the optimal technical solution for tank foundations massively exhibiting underdriven piles

Introduction. Failure to consider the specificity of moraine loam, namely the possible presence of chaotic boulder inclusions, led to the under-driving of prefabricated reinforced concrete piles for tanks (massive in character and irregular in depth). Since technical literature offers no data on the application of piles varying in length in the bearing soil of tanks and no recommendations on possible measures that could prevent such adverse effects, the paper analyzes the current situation, as well as describing an unconventional approach as to how it can be remedied.
Aim: to perform calculations in the PLAXIS 3D and PLAXIS 2D software for various scenarios of interaction between tank foundations and underlying soils.
Materials and Methods. The main objective of the work was to find a technical solution that could remedy the situation involving the underdriven piles. Since the analysis of technical literature revealed no optimal solutions for the foundations and underlying soils of tanks, the authors had to use the PLAXIS 3D and PLAXIS 2D simulation software to explore the possibilities.
Results. It is proposed to use driven piles as elements reinforcing the bearing soil. In addition, it is planned to make a 60 cm thick sand cushion over pile heads with a cut-off level below the design reference mark in order to more evenly distribute the tank load on the underlying soil and to equalize the settlements. The performed calculations were used to select bearing soil stiffness coefficients justifying the foundation slab design adopted in the project.
Conclusions. The study identified the reasons for this negative situation, proposing an unconventional technical solution and determining the coefficients of bearing soil stiffness for performing further tank calculations.

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