Effect of inertial and kinematic interaction on seismic behavior of cement-soil reinforced pile in liquefiable sites
摘要
A shaking table test was performed to investigate the different responses of piles with and without cement-soil reinforcement, considering both inertial and kinematic interactions. A comparison of the dynamic shear stress – strain hysteresis curves of soil profiles on the pile side with and without cement-soil reinforced piles indicates that cement-soil reinforced piles not only bear more tremendous shear stress but also have smaller strains under the action of cyclic shear stress. Furthermore, the cement-soil on the pile side not only shares part of the shear stress and modifies the bending moment distribution but also significantly enhances the resistance of the pile-side soil, reducing the lateral displacement of the superstructure. Cement-soil reinforcement reduced shear strains, inhibited sand liquefaction, and reduced superstructure displacements by 27%–47% (instantaneous) and 40%–65% (permanent). The proportion of horizontal load sharing between cement-soil reinforcement and saturated sand is considered, along with the change pattern of the subgrade reaction after sand liquefaction. An equivalent subgrade reaction calculation method is proposed, which accounts for the horizontal load-sharing ratios of soils with two different strengths. The test results indicate that the pile stress and displacement, estimated using the equivalent subgrade reaction, are in good agreement with the observed results.