卢兰萍，张宇超，李明勋

摘要：為了减小路桥过渡段的差异沉降，缓解软土地区的桥头跳车问题，提出了一种采用CFG桩复合地基联合换填泡沫混凝土加固软基的方案。依托实际工程案例，采用有限元软件MIDAS GTS/NX建立了CFG桩复合地基工况模型与原始工况模型，检验了CFG桩复合地基的有效性，然后建立了CFG 桩联合台后换填泡沫混凝土方案的模型进行固结沉降分析，并验证了两者联合应用的优越性。研究结果显示：1）CFG桩复合地基对于软基的加固效果显著，其工期沉降比原始工况减少了18.32 cm;2）CFG桩复合地基加固软基时，台后换填泡沫混凝土使桥台与路面的台阶型差异沉降相较于台后普通路基填土工况减小了0.72 cm，对于桥头跳车问题的治理效果良好;3）模拟结果与工程实测沉降数据对比误差极小，说明了有限元模拟的可靠性。研究结果有效解决了常见的桥头跳车问题，方案具有更安全、环保、可靠的特点，可为软土地区的路桥过渡段工程提供一定的理论参考与借鉴。

关键词：地基基础工程;CFG桩;泡沫混凝土;软土地基;桥头跳车;数值模拟

中图分类号：U416.1文献标识码：ADOI：10.7535/hbgykj.2021yx06012

Study on the combined application of CFG pile + foam concrete

in solving bump at bridge head on soft soil foundation

LU Lanping，ZHANG Yuchao，LI Mingxun

（School of Civil Engineering，Hebei University of Engineering，Handan，Hebei 056038，China）

Abstract：In order to reduce the differential sedimentation in the transition section and alleviate the problem of bump at bridge head on soft soil foundation，a scheme of CFG pile composite foundation combined with replacement of foam concrete to reinforce the soft foundation was proposed.Based on the actual project，the finite element software MIDAS GTS / NX was used to establish the models of CFG pile composite foundation and original foundation，and the effectiveness of CFG pile composite foundation was verified.Then the "CFG pile composite foundation + foam concrete" model was set up for consolidation sedimentation analysis to verify the advantages of joint application.The results show that：1） the soil settlement of the CFG pile composite foundation is reduced by 18.32 cm compared with the original working condition，which has a significant effect on soft foundation reinforcement;2） compared with the replacement of ordinary filling behind abutment，the combined application of CFG piles and foamed concrete reduces the differential settlement of the bridge abutment and the pavement by 0.72 cm，and the treatment effect the problem of bump at the bridge head is good;3） compared with the measured settlement data of the project，the error of the simulated results is extremely small，which shows the reliability of the finite element simulation.The research results can solve the common problems of bump at bridge head and the scheme has the characteristics of safety，environmental protection and reliability，which  can provide some theoretical reference for the design of transition sections of roads and bridges in soft soil areas.

Keywords：foundation engineering;CFG pile;foam concrete;soft soil foundation;bump at bridge head;numerical simulation

由于桥梁结构为刚性结构，道路基础结构为刚性和柔性的混合结构，在车辆的反复碾压下，路桥过渡段会形成不同程度的差异沉降，产生桥头跳车问题，影响行车舒适性，降低通行能力，增加养护维修费用，甚至引起交通事故[1-2]。尤其是软基地区，因其含水量较高、孔隙大、可压缩性强、抗剪能力较低、固结缓慢，使得这种不均匀沉降更加突出，隐患更大。……