Large-scale shaking table test and three-dimensional numerical simulation research on earthquake seismic failure response of laterally spreading site-pile group-superstructure system

Abstract

The method employed in this study combines large-scale shaking table tests with fully coupled 3D non-linear dynamic analysis to investigate the site response and structural damage mechanisms of laterally spreading site cluster pile foundation systems under weak and strong seismic excitation. The study also aims to verify the applicability of the high-efficiency and universal parallel calculation system method, which involves SolidWorks, HyperMesh, OpenSeesMP, and GiD, with a fully visualized interface operation in geotechnical engineering, based on the test database. The results show that under weak seismic excitation, the acceleration and displacement in the free field and near-pile region are linearly distributed along the burial depth, and the motion of shallow pile foundation is mainly controlled by the inertial effect of the superstructure; while under strong seismic excitation, the displacement in the near-field region is much smaller than the free field showing significant pile pinning effect, and the displacement and acceleration in the near-pile domain are cosine-shaped distributed along the burial depth, with the lateral spreading of site liquefaction intensifying. At the intersection of clay and sand layers, a weak interlayer is present, which affects the structural response. The kinematic effect of the site dominates the response, and the location of vulnerability gradually shifts from the pile bottom to the pile head.

Appendix 1

The equations for different depths in frictional contact are described below.

$${F}_{max}^{h}=({\sigma }_{v}^{,}{K}_{0}tan{\varphi }_{h}+{c}_{h })\times {A}_{h}\times N$$

(2)

$${A}_{h}=\frac{1}{2}\times \pi \times D\times {l}_{h}$$

(3)

$${d}_{D}^{h}=\frac{{\sigma }_{v}^{,}{K}_{0}tan{\varphi }_{h}+{c}_{h }}{{G}_{h}}\times D$$

(4)

$${d}_{l}^{h}=\frac{{\sigma }_{v}^{,}{K}_{0}tan{\varphi }_{h}+{c}_{h }}{{G}_{h}}\times {l}_{h}$$

(5)

$${E}_{D}^{h}=\frac{{F}_{max}^{h}}{{d}_{D}^{h}}= \frac{1}{2}\times \pi \times {G}_{h}\times {l}_{h}\times N$$

(6)

$${E}_{l}^{h}=\frac{{F}_{max}^{h}}{{d}_{l}^{h}}= \frac{1}{2}\times \pi \times {G}_{h}\times D\times N$$

(7)

where, ${F}_{max}^{h}$ is the ultimate frictional resistance; ${G}_{h}$ is the initial shear modulus of the soil; ${K}_{0}$ is the static earth pressure coefficient of the soil; ${\varphi }_{h}$, ${c}_{h}$, ${\sigma }_{v}^{,}$, are the effective internal friction angle, undrained shear cohesion, and initial vertical effective stress of the soil, respectively; N is the number of pile foundations; ${A}_{h}$ is the force area assigned to a single zero-length unit; D is the diameter of the pile foundation; ${l}_{h}$ is the force length of the pile node; ${d}_{D}^{h}, {d}_{l}^{h}$ are the critical pile-soil relative displacements along the pile diameter and pile axis, respectively;${E}_{D}^{h}, {E}_{l}^{h}$ are the frictional contact stiffness along the pile diameter and pile axis.