Constructive and technological solutions for underground space safety amidst dense historical buildings and weak foundation soils

The article considers the issues of geotechnical substantiation and application of constructive and technological measures for the construction of underground space up to 4.4 m deep in the closed courtyard of the Palace built in the 18th century in conditions of weak water-saturated soils in the historical center of St. Petersburg. The underground space of 18.4 x 29.4 m was arranged in close proximity to the enclosing structures of civil buildings built in the 18th - 19th centuries. The article presents design solutions based on the finite element calculation method for strengthening the foundations of existing buildings, enclosing the pit and the foundations of the new structures, which comprehensively ensure compliance with the required safe additional deformations of the surrounding buildings. The results of geotechnical monitoring are presented in comparison with the results of a numerical calculation of the main load-bearing structures of new and existing buildings of the surrounding development during the construction process.