轻型夯法工艺对桥基变形的影响及离散元分析

摘要

旨在分析台背回填施工中轻型夯法工艺对桥基水平位移变形（简称水平位移）的影响．利用颗粒离散元方法分析了桥基在不同碎石土接触刚度、夯击点距结构边缘水平间距（简称夯击间距）、夯击次数、夯锤落高与重量及不同夯锤与路基接触面形状（简称接触面形状）下的水平位移规律．与现场实测值及静止土压力作用下的理论水平位移值进行了比较．结果表明：夯击间距与接触面形状较其他参数对桥基水平位移的影响程度更大；相同夯击能级下，“轻锤高落”比“重锤低落”引起桥基产生的水平位移量值小；有、无夯击垫板情况下桥基产生的最大水平位移为仅在静止土压力作用下的2．65倍、3．56倍．%The impact of light tamping method on the backfill of construction on the deformation of bridge foundation is analyzed.By using the distinct element method,the impact on the horizontal displacement of bridge foundation under different factors,such as the gravel soil contact stiffness,the weight of hammer,the height of hammer,the horizontal spacing of hammer is simulated,and the change rules are found.The measured values of horizontal displacement of bridge foundations during the process of dynamic tamping are compared with the theoretical values under static backfill earth pressure.The result show:The horizontal spacing of hammer has greater effect on the displacement of bridge foundation;Under same tamp energy,“light hammer at lower height”achieves a smaller horizontal displacement than“heavy hammer at higher height”.The maximal displacement deformation of bridge foundation under the action of tamping with or without a tamping plate is 2.65 or 3.56 times of that under static backfill earth pressure,respectively.