类矩形盾构过渡到圆形盾构的设计探研

基于当前城市轨道交通的快速发展,地下线施工的工法日益成熟,类矩形盾构应势而生,该工法能节约地下空间资源,与常规的圆形盾构工法相比,类矩形盾构的优势在于单次掘进即可一次形成双线隧道,能减少土地征用量,显著提高隧道在狭窄道路或高层建筑间的穿行能力,并能最大程度地降低工程对周边环境的影响。结合宁波轨道交通2号线二期工程的实际案例,探讨类矩形盾构工法在地下段使用的可行性,并研究单洞双线类矩形盾构过渡到双洞单线圆形盾构的线路过渡方案,供今后类似工程借鉴。

Design Exploration from Quasi-rectangular Shield to Circular Shield

Based on the rapid development of urban rail transit, construction of the underground line is becoming more advanced, and the quasi-rectangular shield has come into existence as the situation requires. The construction method can save underground space resources. Compared to the conventional circular shield method, the advantage of the quasi-rectangular shield method is the single excavation that can form a double-track tunnel one time, reduce the amount of land requisition, significantly increase the ability to travel between narrow roads or high-rise buildings, and minimize the project impact on the surrounding environment. Based on the practical case of Ningbo Subway line 2 in the recent second phase, this study explores the feasibility of the quasi-rectangular shield used in an underground line and investigates the route transitional scheme from one tube with a two-lane quasi-rectangular shield to two tubes with a one-lane circular shield, which can provide guidance to similar projects in the future.