中文摘要：

采用桩-网加固拓宽路堤时,土拱效应对于分析新老路堤应力分布和差异沉降有至关重要的作用。依托某高速公路路堤拓宽项目对土拱效应进行研究,对试验段新路堤填筑过程及运营时基底桩及桩间土不同位置处土压力、加筋层拉应变进行监测,得到二维平面土拱效应的变化规律,并利用已有土拱效应计算方法对现场实测结果进行对比验证。结果表明,平面土拱作用范围在一定高度范围内,试验段约为2.0 m,即拱高、拱跨之比约为1.4,与英国规范BS8006[1]相近;按Guido法[2]与BS8006法[3]进行土工格栅的设计均过于保守,除Guido法以外,几种方法均低估桩间地基土的承担荷载贡献。因此,需在理论上作进一步研究。

英文摘要：

Soil arching is very important for analyzing the stress state of existing and widening embankment and differential settlement between piles （caps） and subsoil. In this paper, the behavior of soil arching is analyzed for a widening embankment which is supported by rigid piles with caps and reinforced by geogrid. Based on the test site of the widening expressway project, earth pressures on caps and subsoil at the bottom and at different depths to fill surface are investigated; and tensile strains of the geogrid are monitored too. Then stress concentration ratios and soil arching ratios are analyzed and compared with several current design methods, including the Guido method, the BS8006 method, the Kempfert method and the Low method. Results show that, a two-dimensional plane soil arching fill load distribution on caps and subsoil within a critical arch height which is deduced to be 2.0 m owing a ratio of 1.4 the pile clear spacing, and is consistent with BS8006. The Guido and BS8006 methods were too conservative on assessing tensile strain ofgeogrid; Except for the Guido method, all rest presented design methods underestimated the resistance from the compressible subsoil. So, further study and a better understanding of soil arching should be developed.