大直径螺杆桩机变径钻具的结构设计
Structure design of the variable diameter drilling tool of large diameter screw pile machine

为降低螺杆桩机的钻进阻力,实现大直径螺杆桩的施工,提出一种直杆段直径小于螺纹段直径的钻具结构。通过对桩体和钻具进行受力分析,以钻进功率与桩体螺纹段承载力之间的比值最小化为目标函数建立优化模型,并采用MATLAB和ANSYS软件对模型进行计算和仿真,设计一款符合施工要求的大直径变径钻具。结果表明:本文设计的变径钻具不仅使桩体螺纹段承载力提升25%,同时使钻进功率至少降低了16%。此外,变径钻具的构造外型还可以扩展桩机的成桩范围,使“一机多桩”成为可能。
To reduce the drilling resistance of the screw pile driver and implement the constructionof large diameter screw pile, this paper puts forward a kind of drill tool structure of which the straight rod section diameter is less than the threaded section. Through the force analysis of pile body and drilling tools, the optimization model were built, taking the ratio of the drilling tool power to the pile body bear capacity to the minimum as objective function. After using the MATLAB and ANSYS software for model simulation, a large diameter drilling tool of which diameter could varies and function meets the requirements of the construction was designed. Results show that: the variable diameter drilling tool designed in this paper make not only the bearing capacity of pile thread section increase by 25% but also the drilling power decreaseby more than 16%. In addition, the structure of the variable diameter drilling tools can also extend the range of pile forming and made it possible to be the "multipurpose machines"