宁夏某引水工程隧洞围岩变形机理分析及处理

Analysis and Treatment of Deformation Mechanism of Surrounding Rock in a Water Diversion Project in Ningxia

以宁夏中南部某引水工程为对象,研究隧洞软岩的工程特性,为工程设计、施工和安全运用提供科学依据。通过勘探、试验、测试和数值模拟等手段,研究软弱围岩水理特性、胀缩性、流变特性、力学特性和变形机理。从软岩的物质组成、赋存环境等方面揭示了其区域特性方面的差异及软弱围岩变形随环境的变化规律,提出了平缓层状软弱围岩隧洞支护时机及支护措施。宁夏中南部地区广泛分布的白垩系、第三系泥质系列软岩由于其亲水性强,具有胀缩、崩解、流变、时间效应和对环境变化敏感等工程特点,容易引起隧洞的变形破坏,研究成果从开挖方式、保护时机和支护技术方面,为采取有效的措施抑制或减弱泥岩产生对工程不利的变形影响提供依据。

This subject ,based on water diversion project in central southern Ningxia ,studies engineering properties of soft rock in soft rock tunnel and gives the scientific basis for engineering design ,construction and safety operation .In the sub-ject,some properties of weak surrounding rocks ,including the hydro-physical properties,swell-shrink property,rheological properties,mechanical properties and deformation mechanism ,have been studied by several methods of exploration ,the laboratory tests,the in-situ tests,the genetic mechanism method .From composition and existing environmen of the soft rock,it reveals the difference of the soft rock property between areas and the deformation law of the weak surrounding rock with the change of environment .It also puts forward supporting time and supporting measures of the tunnel in the layered soft surrounding rock with gentle occurrence .Due to its its strong hydrophilicity ,a series of argillaceous soft rocks of Tertiary and Cretaceous ,which are widely distributed in central and southern Ningxia area ,have the characteristics of swell-shrink ,slaking ,rheology ,time effect and sensitivity to the environment and are liable to cause the deformation fail-ure of the tunnel.In consideration of the principle of engineering safety and investment control ,this research result puts forward effective measurements that can be taken to inhibit or reduce the adverse impact on the mudstone engineering from excavation method ,protection time and supporting technology .