The Preliminary Physical Modeling On The Earthquake Dynamic Response Of Huangcaoping Tunnel No.2

This paper aims at understanding the law of tunnel in response to the earthquake dynamic profoundly by shaking table test to opening section of Huangcaoping tunnel No.2.The result of shaking table test that has been already launched both at home and abroad is used for reference. This paper summarizes the experience in the choice of testing material, the treatment method of model device and the arrangement of sensing unit. According to the similarity theory strictly, and considering the condition of the testing equipment and numerical simulation result, a series of similarity relation are deducted, such the top management of factor as 1/40 geometric similarity ratio, 1/15 elastic similarity ratio and 1/0.75 density similarity ratio.In consulting a large number of modeling material, this test confirms with barite powder, quartz sand, oxidize zinc, gypsum, glycerine, emulsion and water as elementary material. The compounded materials, which have different proportion of mixture, are regarded as similarity material ofâ…¡andâ…¢type country rocks of Huangcaoping tunnel No.2. The gypsum pipe, which is embedded wire net, is managed as the structure model of tunnel. The support unit is simplified for the steel wire of different diameters. Further more, static and dynamic parameters of similarity material have been test, guaranteeing the similarity demand.On the two-way and three degree of freedom shaking table, the model has been tested, which is input different direction shock waves. At the same time, the acceleration situation, the contact pressure between tunnel structure and country rock, the peripheral pressure of model are recorded. The result of the test shows that when horizontal, vertical or elliptical shock motion, the vault pressure of the tunnel changes relatively largely, comparatively identical with the numerical simulation result. The waist has obvious pressure changes only in the horizontal shock. The contact pressure between model and model case is relatively low. Polystyrene foam has better shock attenuation characteristic. The model can express the spread of seismic wave truly.Finally, the scheme design of large-scale model shaking table test is given on the model case choice, the border treatment, the model procedure and the shaking wave input mode.