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利用振动台进行了在地震激励下冻土、可液化砂土与钢管桩之间的相互作用模拟试验研究.试验设计柔性模型箱装填土体以模拟边界影响,通过配比试验制备混凝土砂浆模拟上覆冻土层,采用饱和砂土作为液化土,利用顶部附加集中质量的方法模拟钢管桩的惯性荷载.试验过程中选取调幅地震波模拟地震激励,通过实时测量桩的应变、桩/冻土位移和砂土内的孔隙水压力等方面的数据,分析冻土层覆盖下砂土的液化情况和与之对应的桩基动力反应情况.试验结果显示:在地基液化发生前,冻土层可以给桩基提供一定的侧向约束,有利于提高其承载力并抑制其侧向变形;然而一旦出现液化,冻土层则可能增强地基液化的趋势,导致桩基承载性能下降.
The shaking table was used to simulate the interaction between frozen soil, liquefiable sand and steel pipe piles under earthquake excitation.Experiment design The flexible model box was filled with soil to simulate the influence of the boundary, and the concrete mortar simulation The frozen soil layer is covered with saturated sand as liquefied soil, and the inertial load of steel pipe pile is modeled by the method of additional concentrated mass at the top. During the test, amplitude-modulated seismic wave is selected to simulate seismic excitation. By real-time measurement of pile strain, Displacement and the pore water pressure in the sand and so on, and analyzes the liquefaction condition of the sand soil under the permafrost layer and its corresponding dynamic response of the pile foundation.The results show that before the foundation liquefaction, the permafrost layer can However, in the event of liquefaction, the permafrost layer may increase the liquefaction tendency of the foundation and lead to the decrease of bearing capacity of pile foundation.