为解决小直径顶管机隧道施工无法洞内拆机和维修以及刀盘上刀具失效后无法更换等难题，开展一种小直径顶管机可回退刀盘的设计研究。通过数值计算方法，确定翻转臂角度的关联因素；从结构设计角度，提出可回退刀盘翻转臂的3大关键性结构设计；采用数值模拟计算，校核刀盘的结构强度并分析渣土流动情况；最终依托厂内试验和工程应用对可回退刀盘的可行性进行验证。研究结果表明： 1）翻转臂的翻转角度需综合考虑旋转中心位置、翻转臂的重心、允许的极限位置、刀具的尺寸和承载力、翻转臂的结构强度等因素； 2）可回退刀盘翻转臂部件的3大关键针对性设计，即连接传扭分离设计、双向限位设计和边缘滚刀变径偏心设计，能满足工程地质情况及设备可靠性要求。

A smalldiameter conventional pipejacking machine cannot be dismantled and maintained in tunnels, and the cutters on the cutterhead cannot be replaced after failure. Therefore, a reversible cutterhead that can be used in a smalldiameter pipejacking machine is designed. A numerical calculation method is used to determine the correlation factors of the turning arm′s angle. Furthermore, three structural designs for the key components of the reversible cutterhead are proposed. The structural strength is examined, and the muck fluidity is analyzed through numerical simulation. Finally, the feasibility of the reversible cutterhead is validated through indoor tests and site application. The results are summarized as follows: (1) Factors, such as the position of the rotation center, gravity center, allowable limit position, size and bearing capacity of cutters, and structural strength, should be considered for the turning arm. (2) Three key-targeted designs of the turning arm, i.e., separation design of connection and torsion, twoway limit design, and eccentricity design of the edge disc cutter, can meet the requirements of engineering geology and equipment reliability.