大粒径碎石桩在桥头软基处理中的应用

Application of Large-size Crushed Stone Piles to Soft Foundation Treatment

大粒径碎石桩能克服由于地基强度较低而难以成桩的问题,它是超软弱淤泥地基土加固处理方法之一。实测资料得到,碎石桩复合地基承载力标准值比天然地基提高了2.8倍左右。实测沉降量比相邻段用砂井加土工布处理,沉降量减少约30%。地基加固效果显著。实测沉降速率表明,只要大粒径碎石桩施工质量得到保证,路堤填筑期基本上可以不考虑填土速率问题。从桥头相邻两种地基处理方式沉降与沉降速率比较分析得到,碎石桩可起到缓冲过渡区的作用,可减轻桥头跳车问题。介绍了大粒径碎石桩在京珠高速公路广珠段某桥头软基处理中的应用。

In this paper, a method for treating soft foundation with large-size crushed stone piles is introduced at a highway-bridge intersection in Beijing-Zhuhai Freeway. It was indicated that, with the large size particles, difficulties in constructing the piles in soft soils with very low strengths could be overcome. The measured data showed that the bearing capacity of the reinforced foundation was 2.8 times higher than that of the original foundation, and the settlement was 30% less than that of the foundation treated with sand wells plus geo-fabrics. The settlement rate data showed that it was not necessary to consider filling rate of the embankment on the foundation with quality large-size crushed stone piles. In addition, analysis of settlements and settlement rates indicated that foundation treated with crushed stone piles could reduce car jumping at the intersection between highway and bridge, compared to that with sand wells plus geo-fabrics.