Shaking Table Model Test And Numerical Simulation Of The Soil-pile-Pier System In Liquefied And Non-liquefied Soil Layers

Study on soil-structure interaction under earthquake actions is attracting great concerns in seismic engineering and geotechnical engineering field, and it will become more complex if there exists the potential effect of soil liquefaction. Shaking table test can be used as an important means to understand and examine the dynamic interaction of the soil-structure system. The study on response characteristics and mechanism of the soil-bridge interaction by shaking table test can help understand the earthquake damage and promote the development of seismic safety of bridges.Based on the construction project of Shuhe Bridge in Shandong Province, two shaking table tests are designed to contain the liquefied and non-liquefied soil layers respectively. The purpose of the two sets of tests is to compare the interaction mechanism of soil-pile-pier and the response characteristics of the piles in the liquefied and non-liquefied soil layers. In addition, the pore pressure change and the interaction of soil-pile-pier in liquefied soil are simulated with FLAC3D software.The test observations, results and simulation results indicate that:1. For the case of low PGA excitation (0.1g), seismic liquefaction is not observed in the test containing the liquefiable soil. Both tests show that the interaction of soil-pile is greatly influenced by the inertia force of the pier top; the peak strain of the pile section appears either at the pier bottom or near the interface between upper two soil layers; only slight difference in peak acceleration between the two tests is observed.2. For the case of high PGA excitation (0.4g), the pore water pressure increases quickly but fades away slowly, and clear liquefaction is observed in the surface soil for the liquefied test. However, the vertical distribution of soil acceleration fluctuate when compared with that of the non-liquefied test, which demonstrated marked increase effect with the decrease of the soil depth. Because of the influence of soil liquefaction, the location of the maximum strain of pile section in the liquefied test is lower than that in the non-liquefied test.3. The simulated results of pore water pressure fit well with the test results. For the case of low PGA excitation, the vertical distribution of the simulated peak bending moment of the pile is roughly consistent with the test results.