Construction of tunnels under the existing metro station

In the context of the active development of the metro system, special attention is given to ensuring the safety of existing buildings and structures located in the construction impact zone. The construction of new tunnels near operational metro facilities may lead to undesirable deformations, including the subsidence of structures or rail threads. The aim of this study is to identify the key factors influencing the subsidence of the shallow station structure of the Moscow Metro during the construction of a tunnel using a tunneling boring machine (TBM) directly beneath it. The initial data are based on results from geotechnical monitoring, compared with the technological parameters of tunneling – the average ground support pressure at the face (p), the volume of ground output for installing one ring (vg), the volume of injected grout into annular void (vi) – as well as geometric characteristics (plan distance (r) and height (h) to the observation point) and the physical-mechanical properties of the soils. It was found that the most significant influence on the subsidence magnitude comes from the following parameters (in descending order of importance): r, vg, p, vi. Based on the identified factors, a subsidence forecasting model was constructed, explaining 90,9% of the sample variance and having a mean squared error (MSE) of 0,1353 mm2, which confirms its high predictive accuracy and its adequacy for practical application.