Study of shaking table model test for seismic response of portal section of shallow unsymmetrical loading tunnel

The whole test scheme is systematically introduced firstly, including test facility, design of similarity ratio, similar materials, design of mould case, measuring technology and so on. Then, the test results which include acceleration characteristic of rock and tunnel structure, laws of geologic strata deformation, and distribution of internal force are analyzed and compared with the numerical analysis results. The analysis results indicate that test and numerical analysis results are in good agreement. Acceleration has an apparent amplification effect which increases obviously at the unsymmetrical loading tunnel surface; the displacement of geologic strata which increases with the heightening of elevation is parabolic distribution; and relative displacement is influenced by rock types. Conjugate 45° directions at the cross-section of tunnel structure are great internal force distributing; internal force of symmetric loading tunnel is anti-symmetric; unsymmetrical loading tunnel has unfavorable internal force and great internal force peak. The results above will have great significance to reasonably comprehend seismic response character of the shallow unsymmetrical loading tunnel and be precious basic data for the aseismic design and construction of practical engineering.