In research on dynamic soil-structure interactions under an earthquake load and as a verification research method, the shaking table test is considered an effective tool. However, the proper model box/container for the test soil should be used. Subsequently, the boundary effect of the model box used in the test becomes a critical factor that has a direct impact on the accuracy of the model test result. In this study, a three-dimensional laminar shear model box consisting of 19 layers of spherical rings is designed and produced. The height and inner diameter of the model box are 1,800 mm and 4,500 mm, respectively. Inter-layer aluminum alloy frames are connected via support members that can move freely in all three directions. A shaking table test using the model box is performed, and the earthquake response is measured via accelerometers buried at various depths and positions in the soil to study the box boundary effects. During the test, AP1000 ground motion used in nuclear power engineering designs is applied to the shaking table from one horizontal direction (X or Y), two horizontal directions (X and Y) or three directions (X, Y and Z). The acceleration time-history diagrams and response spectra at various observation points with identical input directions and different depths are compared. The relative errors of the soil response peak acceleration and acceleration response spectra at observation points located from the box center to the edge are calculated. The test and analysis results demonstrate that the proposed three-dimensional laminar shear model box can accurately simulate an actual scenario with an infinite boundary condition in all three directions, which overcomes the limitation of the currently used laminar shear model box that only supports horizontal earthquake excitation input from one or two directions.
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