岩溶地区高速铁路桥梁桩基后注浆承载特性研究

Bearing Characteristic of Post-grouting of High Speed Railway Bridge Pier Foundation in Karst Area

以京沈客运专线顺义特大桥190#墩钻孔灌注桩为研究对象,采用有限元分析与现场静载试验相结合的方法,对高速铁路桥梁桩基后注浆承载特性进行分析。结果表明:后注浆技术能显著提高高速铁路桥梁桩基极限承载力,减小沉降,极限承载力提高约85.1%,沉降减少约58%。当埋深大于11.5 m时,注浆桩的桩侧极限摩阻力相对于未注浆明显提高,黏性土中约提高2.13倍、粉砂中约提高1.72倍、中砂中约提高2.09倍且砂土的压浆效果优于黏性土,建议将砂层选为压浆层。

The No.190 bored pier of Shunyi Bridge in J ingshen Passenger dedicated line is the research objective in this paper.The bearing characteristics of post-grouting of high speed railway bridge pier were analyzed using f inite element method and on-site static loading test.The results show that the post-grouting may signif icantly increase the ultimate bearing capacity of the high speed railway bridge pier foundation by 85.1%,and reduce the settlement by 58%.When the embedment depth is greater than 11.5 m,the ultimate friction resistance of grouting pile at pile side is obviously higher than that without grouting,about 2.13 times in clay,about 1.72 times in silt,about 2.09 times in middle sand.The grouting effect in sand is better than that in clay;thereby the sand layer is recommended as grouting layer.