新型敞开式小直径TBM装备选型及应用

Equipment selection and application of new open small diameter TBM

【目的】广州北江引水4#隧洞长10.2 km,开挖洞径4.5 m,TBM掘进过程中存在断层破碎带多、花岗岩单轴抗压强度高和TBM掘进效率低三大关键技术难题。【方法】为了解决以上难题,从地层适应性、空间利用率、造价和安全性等方面进行了TBM选型分析,并结合工程实例验证新型敞开式TBM应用效果。【结果】新型敞开式TBM优势包括:(1)新型敞开式TBM由护盾式主机和滑车结构组成,采用敞开式施工工法,护盾相较于常规双护盾TBM更短,最小转弯半径为75 m;(2)提出法向锚杆钻机方案,实现隧洞径向220°钻孔作业;(3)设置应急喷混系统,确保围岩脱离尾盾后尽早进行喷混;(4)刀盘镶嵌耐磨合金,合理减小刀具间距,提高掘进推力和破岩能力;(5)优化出渣系统、支护系统、铺轨、通风除尘等设备空间布置。【结论】结果表明:新型敞开式TBM平均月施工进尺400 m以上,穿越断层破碎带隧洞收敛变形控制在3 mm以内,硬岩段刀具磨损控制效果良好。通过与类似工程对比验证了新型敞开式TBM具备地层适应性强、施工效率高等优势。

[Objective]Guangzhou Beijiang Water diversion 4#tunnel has a length of 10.2 km and a diameter of 4.5 m.There are three key technical problems in the TBM excavation process:more fault crushing zones,high uniaxial compressive strength of granite and low TBM excavation efficiency.[Methods]In order to solve the above problems,this paper analyzes the selection of TBM from the aspects of formation adaptability,space utilization,cost and safety,and verifies the application effect of the new open TBM based on engineering examples.[Results]The advantage of the new open TBM is that:(1)The new type of open TBM consists of a shield-type host and a pulley structure,and adopts an open construction method.The shield is shorter than the conventional double-shield TBM,and the minimum turning radius is 75 m.(2)Propose a normal bolt drilling rig plan to realize Water Resources and Hydropower Engineering Vol.54 No.9 the radial 220°drilling operation of the tunnel.(3)Set up an emergency spray mixing system to ensure that the surrounding rock is sprayed and mixed as soon as possible after it is separated from the tail shield.(4)The tool tray is inlaid with wear-resistant alloys to reasonably reduce the tool spacing and improve the thrust and rock-breaking ability of the excavation.(5)Optimize the space layout of the slag discharge system,support system,rail laying,ventilation and dust removal equipment.[Conclusion]The result show that the average monthly construction intake of the new type of open TBM is more than 400 m,the convergence deformation of the tunnel through the fault fracture zone is controlled within 3 mm,and the tool wear control effect of the hard rock section is good.Through comparison with similar projects,it is verified that the new type of open TBM has the advantages of strong stratigraphic adaptability and high efficiency.