TBM隧道撑靴侧壁围岩承载分析与不良地质处理

Bearing Analysis of Tunnel Surrounding Rocks for Tunnel Boring Machine Gripper and Treatments of Unfavorable Geology

为提高TBM在撑靴侧壁围岩破碎、软弱等不良地质的支撑可靠性,确定可量化的判识依据,制定出相应的处理措施并规范化,以保障掘进效率。结合依托工程的TBM结构设计和掘进参数,分析了TBM推进和支撑系统作用力,建立了撑靴侧壁围岩承载力学模型,对各级围岩直接支撑和方木垫支处理的承载有效性进行了测算表明:1)撑靴与岩体的有效接触面积可作为通过性判定的主要特征量;2)强度准则下的撑靴与岩体许用接触面积应优先保障;3)方木垫支处理时Ⅰ、Ⅱ级围岩岩体相对撑靴的剥落面积不是导致打滑的主要因素。最后接合工程实践制定了4类处理措施及施作要点,为提升不良地质撑靴支撑判识能力,匹配处理措施,减少模筑具有良好的应用效果。

To improve the support reliability of gripper of tunnel boring machines(TBMs)boring in broken and weak surrounding rocks and determine quantifiable judgment basis,corresponding treatment measures are formulated and standardized to ensure tunneling efficiency.Based on TBM structural design and excavation parameters of a case project,the forces of TBM propulsion and support system are analyzed,the bearing capacity model of surrounding rock for gripper is established,and the bearing effectiveness of direct support of surrounding rock and treatment of square wooden cushion support is calculated.The results show the following:(1)The effective contact area between gripper and rock mass can be used as the main characteristic quantity for passability judgment.(2)The allowable contact area between gripper and rock mass under the strength criterion shall be guaranteed preferentially.(3)The flaking area of grades I and II surrounding rocks relative to gripper is not the main factor causing gripper slip during treatment of square wooden cushion support.Finally,four kinds of treatment measures and key points are formulated in conjunction with engineering practice.To improve the identification ability of gripper for unfavorable geology,appropriate treatment measures and moulding reduction have good application effect.