红层软岩隧洞大变形特征及控制措施研究

Study on Large Deformation Characteristics and Control Measures of Red-Bed Soft Rock Tunnel

以狮子山隧洞出口软岩洞段为研究对象,通过现场监测及数值计算,进行了围岩大变形特征分析和在不同衬砌厚度、衬砌支护时机及加临时钢支撑条件下的变形控制措施研究。研究结果表明:二次衬砌厚度以0.7 m为宜,若继续增加至1.0 m,变形减少幅度不明显;初期支护后若及时施作衬砌,围岩变形将得到有效控制,考虑围岩应力调整需一定时间,二次衬砌晚于初期支护5 d~15 d施作较为合适;施作临时钢支撑的洞段变形控制效果显著,但起效范围存在一定局限性。

In order to study the deformation control measures of red-bed soft rock tunnel,this paper takes the soft rock exit section of Shizishan tunnel as the research object.Through field monitoring and numerical calculation,the large deformation characteristics of surrounding rock and the deformation control measures under different lining thicknesses,lining support timing and temporary steel support are studied.The results show that the appropriate thickness of the secondary lining concrete is 0.7 m.If the lining thickness continues to increase to 1.0 m,the reduction of deformation is not obvious.If concrete lining is made in time after initial support,the deformation of surrounding rock will be effectively controlled.Since the stress adjustment of the surrounding rock needs a certain time,it is appropriate to consider that the secondary lining is applied 5-15 days later than the initial support.The deformation of surrounding rock in the tunnel section with temporary steel support is well controlled,but the influence range has certain limitations.