Study on Seismic Response Characteristics of Shield Tunnel in Soil-Rock Combination Stratum

The sharp change of stiffness in the soil-rock combination stratum is weak point seismic design tunnel structure. To explore influence vibration on shield tunnel, section Jinan rail transit line 4 at Olympic Sports Center used as research background. Firstly, two-dimensional numerical model established, and internal force calculation distribution law structure are studied. Then, based third similarity theory, physical relationship derived. shaking-table test soil-rock-structure system carried out. response cross-section studied by analysis. results revealed following: (1) peak bending moment diagram derived from consistent with that obtained test, which has shown experimental methods correct, available for resistance tunnels. (2) deformation, axial force, shear under action S-wave abruptly significantly interface section, difference structural stress between upper lower sides increased 65.5%. excessive changes damage mode tunnel. (3) relative abrupt more significant than so most prone to bending-shear damage.