TBM引水隧洞衬砌管片形式研究

管片衬砌是TBM引水隧洞的主要装配构件，其管片形式是决定衬砌结构安全与TBM隧洞推进速度的关键因素。结合某TBM压力引水隧洞，采用不同的管片形式，建立三维数值计算模型，针对常用的矩形管片衬砌与新型平行四边形管片衬砌，对比分析了典型工况（运行期、检修期）下管片衬砌的应力、管片接缝状态与连接螺杆应力等。结果表明，矩形管片衬砌的环向应力沿水流向的分布更均匀且峰值较小；运行期，平行四边形管片衬砌在接缝处的张开位移和螺杆应力分布更均匀且峰值较小；检修期，平行四边形管片间的接触压力与螺杆应力均较大。由于管片接缝位置的张开位移值安全裕度较大，可优先选取整体结构稳定性较高的矩形管片，在满足衬砌应力不超过混凝土设计强度允许值时，可选择施工进度更快的平行四边形管片。研究结果为TBM隧洞衬砌施工提供了指导。

Study on Segment Types of TBM Diversion Tunnel Lining

The segmental lining is the main assembly component of TBM diversion tunnel, and the segment type is a key factor for determining the lining structure safety and the advance rate of TBM tunnel. Combined with a certain TBM pressure diversion tunnel, three dimensional numerical calculation model has been established by using different types of segment. In view of the commonly used rectangular segmental lining and the new parallelogram segmental lining, comparative analysis of the results has been carried out about the stress of segmental linings, the state of segment joints and the stress of connecting screws under the typical working conditions (operating and overhaul periods). The results show that the circumferential stress along the flow direction of the rectangular segmental lining with a smaller peak value distributes more evenly than that in the parallelogram segmental lining; yet with the parallelogram segmental lining, during operating period, the peaks of opening displacement of joints and screw stress produced are relatively small with uniform distribution; while during overhaul period, the contact pressure and the screw stress produced between the parallelogram segmental linings are comparatively high. Due to the opening displacement of segment joints having larger safety margin, the rectangular segment can be a priority selection for its higher overall structural stability. When the lining stress does not exceed the allowable value of the concrete design strength, the parallelogram segment can be considered for its faster construction progress. The research results provide guidance for the construction of TBM tunnel lining.