Wpływ obiektów głęboko posadowionych na strukturę strumienia filtracji wód podziemnych w obszarze wrażliwym na zmiany warunków hydrogeodynamicznych

The progressive citification of urban spaces results in compacting buildings anddeeper foundation of new objects, and even deepening of existing facilities – to obtain maximumuse of underground space. This process significantly interferes with the geological environ-ment, both in the local (single deep foundation objects) and district (linear objects such as sub-ways, tunnels, sewage collectors, groups of deep foundation objects). In Warsaw, undergroundurbanization extends several dozen meters deep and reaches the upper parts of the Neogenedeposits, often fully intersecting Quaternary deposits. The progressing urbanization, and inparticular the cumulative influence of deep foundation structures, creates a new set of factorswith a potentially significant impact on the hydrogeological conditions of the Quaternary aqui-fer, including also the deep-seated aquifer, so far not having placed under a direct hydrogeodynamic impact. This article presents anassessment of the impact of underground development on the groundwater flow structure, with a particular emphasis on the deforma-tion of the filtration mesh as a permanent result of object built-in into the groundwater stream. The analysis is based on the real casestudy of the implementation of a building located in the area vulnerable to hydrogeodynamic changes, where additionally can occur acumulative impact with underground subway tunnels. Model simulations of the building foundation impact on the hydrogeodynamicconditions of the environment were performed. The results of prognostic model calculations were compared with the observationsof changes in the groundwater level during construction works. The results indicate slight, permanent changes in groundwater levels,an increase in hydraulic gradients and changes in water flow directions. The scope of the changes was considered safe for the environ-ment and building objects, allowing even a deeper foundation, although not devoid of the need for a long-term observation of ground-water levels. The obtained results indicate the usefulness and utilitarianity of numerical modeling methods in the analysis of hydrogeologicalconditioning of deep foundations.