Site surveys in At-Bashi to investigate the geotechnical subsurface conditions

Beginning with the first site visit in June 2022, ILF together with other project partners started the site-specific field works on the planned Hydro4U demonstration hydropower plant in At-Bashi (Kyrgyzstan). The main focus of the site visit was to obtain basic information for the subsequent detailed design works and, in particular, to specify the planned geotechnical subsurface investigations. As part of the planning and design works for hydropower projects, direct subsurface investigations are relevant to be carried out in accordance with international standards (e.g. Eurocode 7) for the geological-geotechnical characterisation of the site-specific ground conditions and to minimize project-specific subsurface risks.

Consequently, site surveys including aerial surveys using a UAV (unmanned aerial vehicle, to create digital terrain models) have been carried out for the Hydro4U project.

Based on these, rotary core drillings have been planned before the end of 2022. The drilling works will be performed in thick alluvial soils (sandy gravels with intercalated silts). In order to obtain information on grain size distributions, packing density, hydraulic permeability, shear strength, groundwater characteristics, and other parameters, continuous core recovery and in-situ geotechnical borehole testing as well as sampling will be required for subsequent laboratory analyses. The drilling works are expected to be performed by the local investor Orion LLC.

ILF will take up these results to carry out the detailed design and perform structural calculations for the concrete structures of two Hydroshaft Power Solution modules and associated structures, verify the stability of the dams of the tailrace channel and design the related erosion protection measures. Finally, ILF will prepare the construction drawings and provide site supervision services during the construction of the demonstration hydropower plant.

The ILF Group is an international engineering and consulting firm that helps its clients successfully execute technically demanding industrial and infrastructure projects all over the world in the following main business areas: Energy & Climate Protection, Water & Environment, Transportation & Urban Spaces and Oil, Gas & Industrial.

Authors: Gabriel Pojer, Christoph Prager, ILF Austria

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Website: www.ilf.com
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Photo credits: ILF