Modelling the interaction of an underground structure with the soil in a megalopolis
Modelling the interaction of an underground structure with the soil in a megalopolis
The paper presents an assessment of the interaction of the elements of the "soil-tunnel" system under conditions of changes in the stiffness of the structure when soil parameters change. The study was carried out using numerical modelling and field tests with cyclic loads typical for such structures. In megacities, large-diameter underground tunnels are being constructed; they are several kilometres long and pass-through soils with different properties. An example of such a facility is the construction of a 3.6 m diameter tunnel in Kyiv with a length of about 10 km. Its depth varies from 5 to 90 m. In some parts of the tunnel, due to long-standing erosion processes, the semi-hard clay surrounding the tunnel is replaced by much weaker flowable sandy loam, so there is a need to strengthen the weak foundation. To evaluate the effectiveness of different options for strengthening the foundation, field tests were carried out by injecting polymer mortars into the soil in different volumes and over different areas, followed by cyclic load tests. During the test of the weak base in its natural state, vertical displacements of 3.7 cm were recorded. These displacements are 2 times higher than in semi-hard clay. The volume of mortar used for the reinforced foundation was justified so that the displacements did not exceed the permissible operational requirements. Subsequently, numerical modelling of the interaction of natural and reinforced foundations with an underground structure at different stages of its life cycle was carried out in a physically nonlinear formulation.
Igor P. Boyko; V. Nosenko; O. Lytvyn
18th European Conference on Soil Mechanics and Geotechnical Engineering (ECSMGE2024)
A - New developments on structural design
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