THE METHOD OF DETERMINING THE RATIONAL TUNNEL FACE PRESSURE BASED ON PREDICTION OF STRESS-STRAIN STATE OF "SOIL-LINING" SYSTEM IN THE BOTTOMHOLE ZONE OF THE TUNNEL DURING THE TUNNELING OPERATION USING TBMC

In this paper the technique of determination of rational values of tunnel face pressure in the bottom of the tunnel in a massif of soft soils based on the analysis of the geomechanical processes occurring in the bottom part of the tunnel during the tunneling with the use of tunnel-boring mechanized complex (TBMC) with active tunnel face pressure (TFP) is described. The technique is based on the use of multivariate numerical simulation for solving complex problems of mechanics of underground structures in a spatial setting based on the interaction schemes with the use of elastic and inelastic mechanical behavior of soils. The paper presents an implementation of the proposed method for determining the rational TFP during the construction of tunnels in engineering-geological conditions of the section between stations "Lesnaya" and "Ploschad Muzhestva" and between the stations "South" and "Danube" of Saint-Petersburg metro. An attempt of verification of the proposed computational method on the results of in-field observations of land subsidence has been performed