刚性与柔性桩承式路堤竖向承载特性分析

Vertical bearing behavior of rigid and flexible piles in pile-supported embankment

基于软弱地基高速公路桩承式路堤现场试验,获得了预应力高强混凝土管桩和高压旋喷桩承载特性随时间的变化规律。现场试验与数值模拟结果对比分析验证了有限元模型界面单元和本构模型选取的有效性。采用有限元数值模拟软件分析了预应力高强混凝土管桩在不同阶段的承载特性,研究了桩长、桩径和面积置换率对桩承式路堤性能的影响,获得了桩承式路堤中刚性桩的设计优化参数。数值计算结果表明,桩帽可显著提高桩体承载力,且桩帽尺寸与桩间距比值对路堤沉降有显著影响,其比值为0.67~0.74时路堤沉降可得到有效控制。

The field tests on the pile-supported embankment of an express way in soft soil area are performed to capture the performance of pre-stressed high-strength concrete pipe piles and high-pressure jet grouting piles with time.The rationality of the selection of interface element and constitutive model used in the finite element numerical simulation software is verified according to the comparison between simulated and field test results.The bearing behavior of the pre-stressed high-strength concrete pipe piles under different construction stages is then analyzed by using the finite element numerical simulation software,and a parametric study is made to assess the influences of pile length,pile diameter and area replacement ratio on the performances of the pile-supported embankment.The optimization parameters of the rigid piles in the pile-supported embankment are obtained.The numerical results show that the bearing capacity of piles can be increased due to the loads shared by the pile cap.The ratio of pile cap size to pile spacing has a significant impact on the embankment settlement,and the embankment settlement can be effectively controlled when the ratio is 0.67 to 0.74.