Key geotechnical design elements at Pulkovo Airport included the excavation of a 6m deep basement and the design of mono-piles to facilitate partial Top-Down construction. The ground conditions at Pulkovo Airport were particularly challenging with highly variable Quaternary Deposits comprising saturated sand channels within impermeable clays, overlying dislocated Cambrian Clays of a high plasticity.
The basement was excavated through the Quaternary Deposits and into the Cambrian Clay, and Ramboll provided an efficient design to both control groundwater during excavation and mitigate short and long term heave. Bearing piles were then designed to allow the partial top-down construction of the terminal. Initially the roof was supported by mono-piles allowing top-down construction to commence prior to basement excavation, however, upon completion of the basement excavation the mono-piles were tied into larger piles caps to support the bottom-up construction of the terminal itself.