基于水压致裂试验的隧道围岩挤压变形与防治措施

Extrusion Deformation of Tunnel Surrounding Rock and Its Prevention Measures Based on Hydraulic Fracturing Test

为研究缓倾层状围岩地质条件下的隧道围岩挤压变形问题,依托贵州金仁桐高速桑树湾隧道项目,对现场不同位置处的围岩变形进行了监测;进行了水压致裂原位试验,根据围岩变形特征和实测数据,提出了一系列隧道围岩挤压大变形的控制措施。结果表明:初期支护完成后,拱顶、拱肩和拱腰变形随时间变化均出现先增大后稳定的趋势;变形量由大到小依次为拱顶、拱肩和拱腰;计算出了隧洞埋深200 m工况下最大切向应力、最大初始应力以及垂向应力;设计了双层初期支护加钢花管注浆的处治措施,体现出了良好的加固效果。

In order to study the extrusion deformation of tunnel surrounding rock under the geological conditions of gently dipping layered surrounding rock,relying on the Sangshuwan Tunnel Project of Jinrentong Expressway in Guizhou,the deformation of surrounding rock at different locations on the site was monitored.The in-situ test of hydraulic fracturing was carried out.According to the deformation characteristics of surrounding rock and the measured data,a series of control measures for large deformation of surrounding rock in tunnel were proposed.The results show that:after the completion of the initial support,the deformation of the vault,spandrel and haunch all show a trend of increasing at first and then stabilizing with time.The amount of deformation from large to small is vault,spandrel and haunch.The maximum tangential stress,the maximum initial stress and the vertical stress are calculated under the condition of tunnel burial depth of 200 m.The treatment measures of double-layer initial support and steel flower tube grouting are designed,which shows a good reinforcement effect.