穿黄隧洞北岸竖井新型反力座结构设计

Design of new type of reaction abutment of working shaft in northern bank of tunnel crossing Yellow River

为解决穿黄盾构竖井已经施工、盾构机外形尺寸却要加长,致使在竖井内无法布置反力架的问题,设计提出,在不增加竖井断面尺寸的情况下,充分利用竖井井壁为盾构机提供出发反力,使原来起防护作用的井壁变成一个承载结构———反力座。设计采用的结构措施为:适当加厚反力座范围的竖井内衬,并与地下连续墙形成联合结构,以充分利用地下连续墙的竖向承载力;同时构建弧形曲梁,以便承受和均匀传递盾构推进油缸的顶力;并通过局部加固反力座范围的井外围土,以便参与对盾构顶力的分担。新型反力座已成功运行,节省了工程投资约800万元,主要的是为盾构机按预定计划顺利出发创造了条件,可供同类工程参考。

After the construction of the shaft of the shield tunnel crossing Yellow River,it is unable to arrange a reaction shelf because of the sudden change of the shield machine size.In order to solve this problem,it is proposed to fully use the shaft wall to provide starting reaction force for the shield machine without increasing cross section of the shaft.Therefore,the shaft wall,which was supposed to have a function of protection,now becomes a load bearing structure,namely,reaction abutment.The designed structural measures are as follows： increase the lining thickness within the range of the reaction shaft and form combined structure with the underground diaphragm wall to fully use its vertical bearing capacity;build arc beams to bear and evenly transmit the pushing force of propel hydraulic cylinder of shield machine;reinforce the surrounding soil of the shaft within the range of reaction abutment to share the pushing force.The new type of reaction abutment was applied and the construction investment was greatly saved,and it was beneficial for the successful start of the shield machine on schedule.