刚性桩加固高速公路软基土拱效应现场试验研究及其与解析解的比较

用刚性桩处理高速公路软基能减小路堤沉降,提高路堤稳定性,缩短工期。土拱对路堤的承载变形性状有重要影响,到目前为止,对路堤中土拱效应的研究还不深入。本文结合某高速公路刚性桩处理软基试验段,实测了路堤填筑过程中及填筑结束后一段时间内桩帽、桩间土土压力及相应的沉降,分析了桩土沉降差、路堤高度、桩间距、桩帽大小等因素对土拱效应的影响,并与现有的几种土拱效应计算方法进行了比较。结果表明:①土拱效应的发挥程度与桩土沉降差密切相关;②当路堤较高,桩间距较小,桩帽较大时,桩体荷载分担比较大;③根据Hewlett&Randolph及陈云敏改进的土拱效应计算方法所得到的桩体荷载分担比与实测结果比较接近。

Field tests on soil arching of highway embankments reinforced with rigid piles and their comparison with current analytical methods

The behavior of embankments is notably influenced by soil arching within embankments reinforced with rigid piles,including the decrease of total and differential settlements,the increase of stability of embankments and the reduction of construction period.However,understanding on soil arching is not enough till now.Soil pressures and settlements obtained from field tests of a highway project were analyzed.It was shown that,soil arching was significantly affected by differential displacements between piles and soil.The higher the embankment height as well as the smaller the pile spacing and the bigger the cap size,the higher the pile efficacy.The pile efficacies calculated by Hewlett &; Randolph and the modified method were in good agreement with the measured data.