摘要:研究目的:榴桐寨隧道是新建成都至兰州铁路线的关键性控制工程，其围岩大变形问题十分突出，而目 前对深埋隧洞围岩流变条件下的变形预测尚无成熟的计算方法。本文在总结现有围岩变形研究成果的基础 上，将隧洞围岩简化为理想弹塑性介质并布设全长锚固锚杆，基于锚杆-围岩协调变形原理，分析杆体表面摩 阻力及其轴力的分布规律，由静力平衡条件推导锚杆中性点处的最大轴力值，进而建立变形稳定后围岩的塑 性区及松动区半径公式，从理论上确定榴桐寨隧道围岩的松动区及塑性区范围，为优化围岩支护方案及参数 提供重要的技术支撑。 研究结论:( 1)工程实际中，围岩流变是导致深埋隧洞出现大变形的根本原因，隧洞围岩变形通常在初期 锚杆支护一段时间后才趋于稳定;（2)隧洞围岩与锚杆协调变形，杆体所受正、负摩阻力的分界面即为杆体中 性点，该点杆体与其周围岩体的相对位移及表面摩阻力为零，但其所受轴向拉力达到最大值;（3)通过锚杆所 受最大轴力可对变形稳定后的隧洞围岩塑性区及松动区范围进行反演分析，围岩塑性区及松动区范围的大 小随岩体黏聚力和内摩擦角的增加而减小，随隧洞半径的增加而增大，但受支护阻力的影响不大;（4)现场应 用结果表明，基于锚杆轴力反分析隧洞围岩分区规律的方法是合理可行的，该研究成果对于类似隧洞工程的 安全快速施工具有一定的借鉴意义。

Abstract ： Research purposes ： Liutongzliai tunnel is the critical engineering of the new railway line from Chengdou to Lanzhou，whose large deformation problem is very prominent， while there is no perfect calculation method for the deformation prediction of the deep tunnel surrounding rock on the condition of rock rheology. Based on the summary of existing research results of surrounding rock deformation，the surrounding rock of the tunnel was simplified as an elastic plastic medium，in which full - column anchor bolts have been laid. This paper analyzed the surface friction and axial force distribution law of the bolt body by the coordination function principle between surrounding rock and bolt and the maximum axial force value of bolt neutral point was derived according to the static equilibrium condition. On this basis， the formulas about the radius of plastic zone and loose zone after the surrounding rock deformation ceased were proposed. Finally，it determined theoretically loose zone and plastic zone range of Liutongzhai tunnel surrounding rock， which provided important technical support for optimization of surrounding rock support scheme as well as parameters. Research conclusions ：( 1) In engineering practice ; rock rheology is the basic reason for the deep - buried tunnel large deformation. Generally speaking, the surrounding rock tends to stabilize after a period of initial bolting support. (2)The surrounding rock and bolt body deform coordinately. The interface of the positive and negative friction on the bolt body surface is neutral point, on which the relative displacement between bolt and surrounding rock as well as surface friction is zero, while the axial tensile force reaches the maximum. ( 3 ) The stable plastic zone and loose zone range of the surrounding rock can be analyzed conversely making use of maximum axial force of bolt body, whose size decreases with increase of the cohesion and internal friction angle of rock mass and enlarges with increase of tunnel radius. It has little relationship with the support resistance. (4) Field application results show that deformation zone distribution laws of the tunnel surrounding rock may be analyzed back on the basis of known bolt axial force. The research findings can be used for reference for safe and rapid construction of similar tunnel engineering.