软岩隧道挤压型大变形非线性流变属性及其锚固整治技术研究

Nonlinear Rheological Features and Anchoring Technology for Soft Rock Tunnel with Large Squeezing Deformation

针对隧道高地应力软弱围岩洞室施工开挖变形与围岩失稳以及衬护结构设计问题,阐述开展岩土流变学研究的必要性以及对软岩挤压型大变形非线性流变问题的研究内容和方法,介绍隧道围岩挤压型大变形的定义、变形特征,及国际上隧道围岩挤压大变形的判定。介绍隧道围岩挤压型大变形非线性流变理论、相应的专用设计软件研制及其工程应用,主要介绍有关的研究内容及其创新性方面;以广义Komamura-Huang流变模型为基础,建立一种能较完整地反映围岩二维、三维大变形非线性流变全过程的Komamura-Huang"弹-线黏弹-非线性大变形黏塑性"流变模型,并在ABAQUS软件基础上进行专用软件的二次开发,将其应用于兰新铁路兰武客运专线乌鞘岭铁路隧道岭脊段围岩5~#断层带中,后又应用于甘南木寨岭高速公路隧道和云南滇中红层引水隧洞2处软岩围岩挤压大变形隧道,采用大尺度让压锚杆/预应力长让压锚索进行了整治研究,并分别进行了二维和三维非线性大变形黏弹塑性数值模拟分析。指出有待进一步深化研讨的若干问题。总结针对软岩挤压型大变形沿用现行刚性支护方案的不合理性和失效教训。提出管控/约束隧道围岩大变形持续发展的让压支护锚固技术措施——一种新型大尺度让压锚杆/预应力让压锚索,介绍让压锚具的受力机制及构造,强调其10个关键性设计施工参数。以兰州木寨岭高速公路隧道围岩挤压型大变形非线性流变分析与采用让压锚杆进行工程整治的试验段情况为例,对该隧道围岩挤压大变形进行二维数值模拟,并对施作让压锚杆进行工程整治的主要有关设计参数进行分析计算。"边支边让、大尺度让压锚杆"方法已先后在几处工程中得到了成功实施,取得了应有的经济效益,其工程技术收益应更受业界关注。

The deformation and instability of surrounding rock and lining structure design of soft rock tunnel with high geostress are very important. The necessity of study of rock and soil rheology and study content and method for nonlinear rheological features of large squeezing deformation of soft rock are presented;and the definition, characteristics and international determination of large squeezing deformation of tunnel surrounding rock are introduced. The nonlinear rheological theory of large squeezing deformation of tunnel surrounding rock and its corresponding special design software development and engineering applications are introduced;and the main contents and innovations are introduced emphatically. An elastic-linear-viscoelastic-nonlinear large deformation viscoplastic rheology model is established based on Komamuro-Huang rheology model, which can well reflect the nonlinear rheological process of 2 D and 3 D large deformation of surrounding rock;the secondary development is carried out on special software based on ABAQUS, which is applied to #5 fault at ridge section of Wushaoling Railway Tunnel on Lanzhou-Wuhan Railway;the large-scale yielding bolt/prestressed yielding bolt is used in Muzhailing Highway Tunnel and Dianzhong Hongceng Water-diversion Tunnel with large squeezing deformation;and the 2 D and 3 D viscoelastic-plasticities of nonlinear deformation are numerically analyzed respectively. Some issues need to be further studied are pointed out. The irrationalities and failure lessons of rigid support for large squeezing deformation of soft rock are summarized. A new yielding supporting and anchoring technology, large-scale yielding bolt/prestressed yielding bolt, is developed, and the force mechanism, structure and 10 key design and construction parameters are introduced. The 2 D numerical simulation is carried out for large squeezing deformation of surrounding rock by taking nonlinear rheological analysis of large squeezing deformation of Muzhailing Highway Tunnel and application of yielding bolt for example;and the key design parameters of yielding bolt is analyzed and calculated. The large-scale yielding bolt/prestressed yielding bolt has been successfully applied to several projects, and good social and economic benefits have been achieved.