T接头受力复杂，易引发安全事故，为确保盾构施工安全,分析正线隧道管片弱化效应，针对主隧道特殊管片的设计施工，开展机械法联络通道刀盘切削试验，模拟始发端混凝土管片掘进切削过程，揭示刀具在不同时刻切削力的变化情况及管片、螺栓在不同工况下的内力分布规律。通过研究得到以下结论： 1)刀具切削厚度、切削速度越大，切削阻力越大，混凝土裂纹扩展越严重，刀具磨损越严重；基体强度越大的混凝土，切削时混凝土板面受损越小。2)切削对同一环的螺栓影响较大，对侧边的螺栓影响较小，随着刀盘旋转推进，管片发生位移变化，螺栓连接点的位移逐渐增大。当刀盘钻出管片时，混凝土管片及内部螺栓位移逐渐趋于稳定。3)改变切削洞口管片的强度对于隧道的变形影响很小，在改变了切削洞口强度后，洞口管片所受的位移增大，但是影响量比较小，结构仍较安全。

The Tjoint has complex forces and is easy to cause safety accidents. To investigate the weakening effect of the main tunnel segment and ensure the safety of shield tunneling, a cutting test is conducted on the shield cutterhead used in mechanical connection channel, the excavation and cutting process of the concrete segment at the launching end is simulated, and the change of the cutting force of the tool at different moments and relationship curve and the distribution law of internal forces of segments and bolts under different working conditions are revealed. The following conclusions are obtained:  (1) The greater the cutting thickness and speed of the tool, the greater the cutting resistance, the more obvious cracking of the concrete and the serious tool wear. The greater the strength of the base concrete, the less damage to the surface of the concrete during cutting. (2) The cutting of tube segments has a greater impact on the bolts of a same ring, and less impact on the bolts on the side. As the cutterhead rotates and advances, the displacement of the tube segments changes, and the displacement of the bolt connection points gradually increases. When the cutterhead drills out of the segment, the displacement of the concrete segment and the internal bolt gradually stabilizes. (3) Changing the strength needed to cut the segment has little effect on the deformation of the tunnel. After changing the cutting strength, the displacement of the tunnel segment increases, but the influence is relatively little, and the structure is still in safe.