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对沪杭城际高铁某桥墩低承台群桩桩基在承台上部加载及地下水位下降导致的沉降特性进行了研究,并对桩-土摩擦系数和群桩的桩间距对群桩沉降影响进行了分析。地下水位下降对群桩的影响机理分析表明:群桩周围一定范围内的水位下降土体所受浮力消失是导致桩体受到向下附加摩阻力及群桩附加沉降的起因;桩-土摩擦系数增大时,降水导致的桩体最大附加轴力出现位置深度越浅,因此,桩体受到向上附加摩阻力的区段长度越大,桩端的附加荷载与附加沉降越小;桩间距增大时,水位下降导致的桩体附加压缩量越大,同时桩端的附加荷载与附加沉降也越大。
The settlement characteristics caused by the upper loading of pile caps and the lowering of groundwater level at a bridge pier of Shanghai-Hangzhou intercity high-speed railway were studied. And the influence of pile-soil friction coefficient and pile spacing on pile settlement Analyzed. The mechanism analysis of the influence of groundwater level drop on pile groups shows that the disappearance of the buoyancy caused by the falling of water level within a certain range around the pile groups is the cause of additional downward friction and the additional settlement of pile groups. The larger the additional axial force of pile is, the shallower the depth of pile is. Therefore, the greater the length of the section subjected to the additional upward frictional resistance, the smaller the additional load and additional settlement of pile tip. When the pile spacing increases , The greater the additional compression of the pile caused by the water level drop, and the greater the additional load and additional settlement at the pile end.