砂土液化分析方法对连续梁桥地震响应的影响对比研究

发布时间：2018-10-11 09:56

【摘要】：为了研究液化场地下桩-土共同作用对连续梁桥地震响应的影响,基于McGann指数衰减函数,提出了修正p-y曲线法模拟砂土液化效应。以某三跨连续梁桥为工程背景,对比研究了墩底固结法、土弹簧法、m法以及修正p-y曲线法对桥梁地震响应的影响,并对液化层厚度和埋深进行了参数分析。研究表明:墩底固结法和土弹簧法大大高估了液化场地下桩基的刚度,导致桥梁内力响应偏大;采用修正p-y曲线法得到的桥梁内力响应最小,但主梁位移却远大于其余三种方法,说明砂土液化对桥梁最不利的影响在于过大的位移;随着液化层厚度的增大,桥梁内力响应先下降后趋于稳定;液化层埋深的变化对桥梁内力响应的影响较小;m法得到的桩顶附近内力远大于p-y曲线法,而在桩身中部则明显低于p-y曲线法,因此按照m法进行桩身配筋时可能导致桩顶偏保守,桩身中部偏不安全。
[Abstract]:In order to study the effect of underground pile-soil interaction in liquefaction field on seismic response of continuous beam bridges, a modified p-y curve method was proposed to simulate the liquefaction effect of sand and soil based on the McGann exponential attenuation function. Taking a three-span continuous beam bridge as the engineering background, the effects of consolidation method of pier bottom, soil spring method, m method and modified p-y curve method on the seismic response of the bridge are comparatively studied, and the parameters of the liquefaction layer thickness and buried depth are analyzed. The results show that the stiffness of underground pile foundation in liquefaction field is greatly overestimated by consolidation method of pier bottom and soil spring method, and the response of bridge internal force is larger, and the response of bridge internal force obtained by modified p-y curve method is the smallest. However, the displacement of the main beam is much larger than the other three methods, indicating that the most adverse effect of sand liquefaction on the bridge is the excessive displacement, and with the increase of the thickness of the liquefaction layer, the internal force response of the bridge decreases first and then tends to be stable. The variation of buried depth of liquefaction layer has little effect on the internal force response of bridge, and the internal force near the pile top obtained by m method is much larger than that by p-y curve method, but it is obviously lower in the middle of pile body than that by p-y curve method. Therefore, the reinforcement of pile body according to m method may lead to conservative top of pile and unsafe middle part of pile body.
【作者单位】：重庆交通大学土木工程学院;同济大学土木工程防灾国家重点实验室;
【基金】：重庆市基础与前沿研究计划项目(cstc2015jcyjA 30014) 国家自然科学基金资助(项目批准号:51408089)
【分类号】：U442.55

【参考文献】