新型集土式扩底钻具的研制与试验应用

针对现有机械式扩底钻具在旋挖钻进施工过程中存在扩孔与取土、清孔分离、工序复杂、孔内沉渣难以清理干净、施工效率低等问题，研制了新型集土式扩底钻具。重点介绍了扩底桩设计理论，集土扩底钻具结构设计，关键零部件有限元数值分析和优化改进，以及样机试制和现场试验。试验结果表明：新型集土式扩底钻具集扩孔、集土功能于一体，减少了工艺步骤，提高了工作效率，满足了旋挖钻进扩底桩的施工需求。

Development and Application of New Type of Soil Collecting Bottom Expanding Drilling Tool

In view of the problems of existing mechanical bottom expanding drilling tool in rotary drilling construction, such as separation of hole expanding from soil taking and cleaning, complicated processes, difficult sediment cleaning and low construction efficiency, a new type of soil collecting bottom expanding drilling tool is developed. This paper focuses on the design theory of underreamed pile, the structure design of the soil collecting bottom expanding drilling tool, the finite element numerical analysis and optimization improvement of the key components and the prototype trial manufacture as well as field tests. The test results show that this new type of soil collecting bottom expanding drilling tool integrates functions of reaming and soil collecting to reduce the technological processes and improve working efficiency, which meets the construction requirements of rotary drilling for underreamed pile.