接杆搅拌桩在低净空条件下铁路软土地基加固中的应用研究

针对低净空条件下的临近既有线铁路路基地基加固问题，提出了接杆搅拌桩处理方案，并进行了现场试验。对施工工艺、桩机研发技术路线、技术创新点、技术经济和工效进行了分析。在技术可行的条件下，重点对接杆桩施工全过程的各环节进行了工效分析，并提出了改进措施。结果表明:接杆搅拌桩适用于铁路低净空条件下的临近既有线施工，适用范围广；通过优化工艺工法、减少接杆数量及完善拆接对中措施，可以提升接杆搅拌桩的施工工效，获得较高的经济和社会效益。

Study on Application of Extension-rod Mixing Pile in Railway Soft Soil Foundation Reinforcement under Low Clearance Condition

In view of the subgrade reinforcement of adjacent existing railway under the condition of low clearance, this paper puts forward the treatment scheme of extension-rod mixing pile and carries out the field test. The construction technology, the technical route for R & D of pile driver, technical innovation point, technical economy and work efficiency are analyzed. Under the condition that the technology is feasible, the paper analyzes the work efficiency of the whole construction process of extension-rod pile, and puts forward the improvement measures. The results show that the extension-rod mixing pile is applicable to the construction of adjacent existing railway lines under the condition of low clearance, with wide range of application. By optimizing the technological method, reducing the number of extension rods and perfecting the measures of disconnection and centring, the construction efficiency of extension-rod mixing piles can be improved and higher economic and social benefits can be obtained.