桥头段刚性桩复合地基现场观测结果分析

对于深厚软土路基,桥面和路面之间常发生较大的沉降差,产生“桥头跳车”现象。浙江台州浃里陈大桥对低强度桩复合地基处理桥头段软土路基进行了试验研究,并采用变桩长的方式调整桥面和路面的沉降差。采用复合地基使该桥头段的路基沉降减少了2/3,加固效果明显。由于采用了不同的桩长,复合地基沉降沿路堤长度方向分布是均匀的。对现场观测结果进行了分析,包括对路堤下桩顶和桩间土的土压力及沉降和复合地基分层沉降观测结果的分析。

FIELD SURVEY OF COMPOSITE FOUNDATION WITH RIGID PILES UNDER EMBANKMENT

When a highway is built on soft clay,vehicles will bounce when they run through a bridge approach because of large settlement difference between a bridge and embankment. Jialichen Bridge uses a composite foundation of rigid piles with different length along embankment to reduce the settlement difference. Embankment weight is a kind of flexible load and prototype observation analysis is reasonable way to study composite foundation under embankment. The prototype observation shows that because settlement of soil is larger than that of piles,an arch effect appears in the embankment so that its weight is gradually transferred from the soil to piles and pile-soil stress ratio increases. Due to the composite foundation,two-thirds of natural foundation settlement is removed. It is more significant that the road surface is basically smooth because of the piles with different length along the embankment. The observation of settlement in different depth shows that larger deformation is developed in the layers nearby the stabilized layer bottom.