高速铁路CFG桩复合地基应力特性试验研究

In-situ Test of Stress Characteristics of CFG Pile Composite Foundation of High-speed Railway

结合京沪高速铁路凤阳试验段,重点开展CFG桩+桩帽+加筋垫层联合堆载预压处理地基试验。实测路堤填筑堆载过程中及堆载结束后一段时间内桩帽、桩间土压力及相应褥垫层顶面的土压力;分析CFG桩复合地基中桩帽顶水平面应力、褥垫层顶面应力及桩土应力分担比随填筑高度和固结时间的变化规律,以及桩帽顶水平面与褥垫层顶面应力在路堤横断面的分布特征;探讨土拱效应形成条件及作用范围。研究成果可为高速铁路软土路基处理提供参考。

Relating to the pile-soil and reinforced cushion cooperative function, the CFG pile composite foundation is so complicated that it is designed mainly by experience, thus its application being limited. It is very difficult for the CFG pile composite foundation mechanism to be researched by theoretical analysis. Insitu full scale tests of the stress characteristics of the composite foundation were carried out in the Fengyang Experimental Section of the Beijing-Shanghai High-speed Railway in respect of the pile, pile cap, reinforced cushion and surcharge preloading. On the Basis of the test data of the pile cap, soil and cushion, the changing law of the level and distribution of pile-soil stresses and cushion stresses with the height of the embankment fill and consolidation time were analyzed. The feature of the soil arching effect was studied. The research results can provide references to treatment of the soft subgrade of high-speed railways.