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通过数值模拟分析了高速公路碎石桩复合地基在桩体施工、路堤填筑、运行期全过程问题和地震动荷载作用等问题。计算结果表明:碎石桩在路堤的填筑和运行期起到明显的排水固结作用,当桩长大于6 m后复合地基中的孔压最大值变化较缓慢;在桩长大于10 m后路堤底面的沉降量和坡脚的水平位移量变化均较小。地震荷载作用下路堤顶部的水平向加速度峰值较底面大;在碎石桩加固范围内,复合地基的水平刚度大于天然地基,而在整个地基内,复合地基的竖向刚度均大于天然地基,在地基刚度较大的情况下位移最大值较大;天然地基在路堤坡脚下方、路堤边坡等位置较易发生液化,经过碎石桩加固后降低了地基液化的可能性。
Through the numerical simulation, the problems of pile foundation construction, embankment filling, the whole process of operation period and the action of seismic load of the highway gravel pile composite foundation are analyzed. The calculation results show that the gravel pile plays a significant role in drainage consolidation during the filling and operation of the embankment. When the pile length is greater than 6 m, the maximum pore water pressure in the composite foundation changes more slowly. When the pile length is greater than 10 m The settlement of the embankment bottom and the horizontal displacement of the slope foot are smaller. Under the seismic load, the peak of horizontal acceleration at the top of the embankment is larger than the bottom. Under the reinforcement of gravel piles, the horizontal stiffness of the composite foundation is greater than that of the natural foundation. In the whole foundation, the vertical stiffness of the composite foundation is greater than that of the natural foundation. When the foundation stiffness is larger, the maximum displacement is larger. The natural foundation is prone to liquefaction under the foot of the embankment and on the embankment slope. After being reinforced with gravel piles, the liquefaction potential of the foundation is reduced.