Centrifugal shaking table test and numerical simulation ofdynamic responsesof straight pile groupin saturated sand

The analysis of lateral dynamic responses of high cap straight piles in saturated sand liquefaction sites is a hot and difficult point for geotechnical engineering. A 2×2 group straight pile model insaturated sand liquefaction sites was designed, and the centrifuge vibration test was carried out to analyze the dynamic responses ofpiles and soilinliquefaction sites. The sand liquefaction large deformation constitutive model was introduced into ABAQUS finite element software platform and the finite element mesh adaptive adjustment technique was used to overcome the large deformation distortion problem. A 2D finite element model for simulating the static and dynamic coupled nonlinear interaction of pile foundations in liquefiable sites was established and compared with the test. The test results show that, in the case of the sine wavewith a peak acceleration of 0.3g, the liquefaction rate of the saturated sand foundation is very fast. The peak accelerations of both the pile capand the soil will not exceed the input wave peak, and the acceleration of the pile cap begins to attenuate after the ground liquefies. The development of the excess pore water pressure in saturated sand soil directly affects the acceleration response, and the liquefaction of soil directly leads to acceleration attenuation. The acceleration dynamic response behavior by numerical simulation issimilar tothat from the experimental test, andthe scaled-down results of numerical simulation are approximately equal to the experimental results. The excess pore water pressure and the excess pore pressure ratio obtained from simulation and test are consistent. The simulation results also indicate that the shallow soil liquefies more obviously than the deep soil and that the displacement of the pile cap is smaller than that of the test. © 2020, Science Press. All right reserved.