沿海软土地区PHC管桩-土-结构模型振动台试验

发布时间：2018-05-19 23:06

  本文选题：桥梁工程 + PHC管桩　； 参考：《中国公路学报》2017年10期

【摘要】：为了解沿海软土地区PHC管桩在地震作用下的动力反应、桩-土动力相互作用特性以及破坏模式,开展PHC管桩-土-结构模型体系的地震模拟振动台试验研究。通过输入3种不同地震波,并逐渐增加地震波峰值,研究预应力度、土体特性对模型体系的地震响应与破坏模式的影响。研究结果表明:土体饱和与否对模型体系的动力特性和地震响应影响较大,PHC管桩的预应力对其动力特性有一定影响,破坏模式也不相同;土体未饱和时,基本烈度地震作用下PHC管桩的一阶频率下降不大,土体饱和时,随着地震波激励的增加,模型体系的自振频率逐渐下降、阻尼比逐渐增大,PHC管桩-土-结构间的相互作用加大,结构开始损伤破坏,频率最大下降至初始频率的50%;预应力的存在可较显著地减缓地震作用下结构的损伤破坏;加速度峰值越大或者土体越深,孔压比越大,最大超过1.0,并出现液化现象,且液化持续时间远大于地震波持时。研究结果可为沿海软土地区PHC管桩的应用和规范的制定提供参考。
[Abstract]:In order to understand the dynamic response, pile-soil dynamic interaction and failure mode of PHC pipe pile in coastal soft soil area, the shaking table test of PHC pipe pile-soil-structure model system was carried out. By inputting three kinds of different seismic waves and increasing the peak value of seismic wave gradually, the influence of prestress degree and soil characteristics on the seismic response and failure mode of the model system is studied. The results show that whether the soil is saturated or not has a great influence on the dynamic characteristics and seismic response of the model system. The prestress of PHC pipe pile has a certain influence on its dynamic characteristics, and the failure mode is also different, and when the soil is not saturated, The first order frequency of PHC pipe pile decreases little under the action of basic earthquake intensity. When the soil is saturated, the natural vibration frequency of the model system decreases gradually with the increase of seismic wave excitation, and the damping ratio increases gradually, and the interaction between the pipe pile and soil-structure increases with the increase of damping ratio. The structure begins to damage, the maximum frequency decreases to 50% of the initial frequency; the existence of prestress can significantly slow down the damage and damage of the structure under earthquake; the larger the acceleration peak value or the deeper the soil, the greater the pore pressure ratio. The maximum is more than 1.0, and liquefaction occurs, and the duration of liquefaction is much longer than that of seismic wave. The results can be used as a reference for the application of PHC pipe piles and the formulation of specifications in coastal soft soil areas.
【作者单位】： 福州大学土木工程学院;福建建筑科学研究院;
【基金】：国家自然科学基金项目(51578161,51278126)
【分类号】：U443.1;U446.1
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本文编号：1912082