武汉地铁4号线盾构始发端设计与施工技术

盾构始发是盾构隧道施工中的关键风险点。结合武汉地铁4号线区间竖井处的盾构始发工程，研究了其加固范围、加固技术参数、洞门破除和密封的方法以及负环管片拼装的技术要点等。研究表明：对于类似武汉地铁4号线软土加粉土、粉砂的地层，土体的横向加固尺寸只要能够满足工艺构造要求即可，较适宜采用三轴深层搅拌桩＋高压旋喷桩的加固方式，洞门密封的时机以及负环管片的稳定对盾构的安全始发都极其重要。

Shield Launching Shaft Design and Construction Technology for Wuhan Metro Line 4

With shield Launching shaft in section for Wuhan metro line 4 project, the paper discusses the studies on reinforcement, strengthening technical parameters, methods of portal launching opening and sealing, as well as the key technologies of negative ring segment assembly. The study shows that horizontal soil reinforcement dimension as long as they meet the requirements of the technical construction for the soft clay and floury soil, mealy sand similar to Wuhan metro line 4, it is appropriate to use the reinforcement of tri-axial deep mixing pile ＋ high pressure jet grouting pile. Meanwhile portal sealing timing and negative ring segment stability play extremely important roles in shield engineering.