考虑路堤填筑过程与地基土固结相耦合的 桩承式路堤土拱效应分析

 土拱效应分析是桩承式路堤设计时需要解决的首要问题，在总结分析已有现场测试资料及研究成果的基础上，建立能考虑路堤填筑过程与地基土固结相耦合的土拱效应计算模型。该计算模型比较完整地反映了从路堤开始填筑直到地基土固结完成整个过程中土拱效应的发展变化历程，模型计算结果与现场实测结果比较吻合。利用该计算模型对台缙高速公路工程桩承式路堤土拱效应及桩身中性点位置的变化特征进行分析，研究结果表明：(1) 在路堤填筑过程中，桩土应力比迅速增加，路堤填筑完毕直至地基土固结完成这个过程中，桩土应力比虽然有所变化，但变化的幅度不大，与路堤刚填筑完毕时的桩土应力比相比，后期桩土应力比的变化幅度不大于15%；(2) 在路堤填筑及地基土固结过程中，桩身中性点位置经历了先逐渐向下移动、尔后向上移动、再向下移动、最终趋于稳定位置的过程。该研究成果可为桩承式路堤设计提供有益的参考。

ANALYSIS OF SOIL ARCHING IN PILED EMBANKMENTS CONSIDERING COUPLED EFFECT OF EMBANKMENT FILLING AND SOIL CONSOLIDATION

The analysis of soil arching is the first important issue for the design of piled embankments. An analytical model for soil arching within piled embankments is developed，which can consider the coupled effect of the embankment filling and soil consolidation. The calculated values of the stress concentration ratio using the proposed model herein are in good agreement with the field measurements. This demonstrates that the model can reflect the variation characteristics of soil arching with time. A further study of characteristics of soil arching and the neutral point of pile shaft during the embankment filling and the soil consolidation was also conducted. The results show that：(1) With the embankment filling，the stress concentration ratio increases and reaches a maximum value at the end of filling，then decreases about 15 percent of the maximum value and maintains nearly a constant value. (2) During the embankment filling and soil consolidating，the location of the neutral point of pile shaft descends firstly，then ascends till the end of embankment filling. With the continuous consolidating of soil，the depth of the neutral point becomes deeper，and at the end of soil consolidating，the location of the neutral point is unaltered. The obtained conclusions can provide valuable references to engineering design.