铁路盾构隧道接触网基础局部预埋槽道方案研究

Research on the Proposal of Catenary Local Embedded-Channel in Railway Shield Tunnel

相对于城市轨道交通,双线铁路盾构隧道具有洞径大、管线入槽的特点,全环预埋槽道利用率低,会造成极大的工程浪费,对接触网基础局部预埋槽道研究十分必要。根据接触网布设功能需求,将常规的六种槽道类型优化为两种,其中Ⅰ型槽道主要用于接触网吊柱与附加线悬挂,Ⅱ型槽道主要用于结构下锚。结合盾构隧道现场施工,按照固定槽道环管片,调整负一管片拼装点位的设计方法,以及影响因素中楔形量高于通缝数量、高于K块点位的原则,分段落进行拼装点位优先级排序。对于右偏曲线,预埋槽道布置于A5块,负一环管片拼装点位优先级为3>2>21>22>4>1;对于左偏曲线,预埋槽道布置于A1块,负一环管片拼装点位优先级为9>13>10>12>4>11;对于直线段,预埋槽道布置于A1、A5块,负一环管片拼装点位优先级分别为2>22、12。以国内某大直径铁路工程为例,相较于后植锚栓方案,局部预埋槽道方案折合单位使用寿命减少约2.67万元/年,综合分析,具有较好的经济效益与推广价值。

Compared with urban rail transit,the double-track railway shield tunnel has the characteristics of large tunnel diameter and pipeline entering the groove.The utilization rate of full ring embedded channel is low,which will cause great engineering waste.It is significant to research the local embedded-channel of catenary in double-track railway large-diameter shield tunnel.According to the functional requirements of catenary,the types of embedded channels are simplified from six to two,theⅠ-type is used for catenary suspension post and additional line suspension,and theⅡ-type is used for structure anchoring.Combined with the on-site construction of the shield tunnel,according to the design method of fixing the channel ring segment,adjusting the assembly point position of negative segment 1,and the principle that the wedge amount is higher than the number of through joints and higher than the point position of K block in the influencing factors,the assembly point position is prioritized in sections.For the right curve paragraph,the embedded channel is arranged in block A5,and the priority of the assembly point for the negative segment is 3>2>21>22>4>1.For the left curve paragraph,the embedded channel is arranged in block A1,and the priority of the assembly point is 9>13>10>12>4>11.For the straight line paragraph,the embedded channel is arranged in A1 and A5,and the priority of the assembly point is 2>22 for the former,and it is 12 for the latter.Taking the railway large-diameter shield tunnel project as an example,the investment of local embedded-channel program is equivalent to the unit service life of 26,700 Yuan less than the post-anchorage program.In summary,the former has better economic benefits and promotion value.