【摘要】 通过振动台模型试验,在考虑土-桩-结构相互作用的条件下研究PHC管桩的抗震性能。试验采用层状剪切土箱,装填黏土、粉土、砂土3种土体,分别安装单桩、三桩和六桩3个模型。对每个模型施加3种不同的地震波,5种不同的振动强度。结果表明:随着振动持续,各模型体系的自振频率降低,阻尼增大。随着震级增加,土-桩-结构间的相互作用影响加大,土体及土-桩-结构体系的非线性增强,且少桩体系的非线性性质要强于多桩体系。桩的数量和布置方式以及上部结构的变化均极大地影响着桩体应变和弯矩的大小及分布规律。三桩、六桩模型最大拉应变比单桩模型分别下降23%和66%,最大弯矩分别下降29%和70%,桩-土界面压力分别下降22%和32%。多桩体系的震动破坏程度也远弱于少桩体系。初步确定PHC管桩在高烈度地区的应用是可行的,值得进一步研究。更多还原

【Abstract】 A shaking table model test of the earthquake performance of PHC pipe pile under seismic excitations considering soil-pile-structure interaction effect is presented.Features of the shaking table test include a variety of pile models,i.e.single pile,three piles,and six piles,and a shear soil box consisting of clay,silt,and sand layers.The various developed soil-pile-structure systems are then subjected to three sets of seismic ground motions.Each set of the earthquake events is composed of five input excitation scenarios with varying intensities.The evaluation results show that along with earthquake continues,each model system natural frequency decreases and damping increases.The earthquake intensity has a significant effect on the soil-pile-structure system.Specifically,the soil-pile-structure interaction and soil nonlinearity effects are observed to go up as the intensity increases.The nonlinearity effects of systems with fewer piles are stronger than those with more piles.Moreover,the number and arrangement pattern of the piles as well as the configuration of the upper structure can exert substantial impact on the strain and bending moment responses.It is shown that compared to the single-pile model,the maximum tensile strains of the three-pile model and six-pile model drop by 23 percent and 66 percent respectively,whereas the maximum bending moments decrease by 29 percent and 70 percent respectively.On the other hand,the soil-pile interface pressure reduces by 22 percent and 32 percent respectively.It is also found that the damage behaviors for systems with more piles are less severe than those with fewer piles.The results of this preliminary investigation further indicate the feasibility of exploiting PHC piles in high seismicity regions.Nonetheless,it is also suggested that more research efforts are required for extensive application of PHC piles in such areas.更多还原