乌鞘岭隧道千枚岩地层初期支护参数研究

研究目的:针对乌鞘岭隧道深层地段千枚岩地层,隧道开挖过程中,围岩产生大变形的特点,进行初期支护合理性的研究,提出有效的支护措施。研究方法:结合兰武二线乌鞘岭隧道岭脊地段千枚岩地层的设计施工,采用动态设计方法,根据千枚岩不同含量,确定试验段,布置量测断面,通过现场位移量测,分析总结深埋条件下,千枚岩地层变形特点和初期支护设计方法。研究结果:通过对隧道开挖过程中围岩变形和初期支护的研究,提出了千枚岩地层初期支护参数的建议方案,对同类工程的设计施工有一定的借鉴意义。研究结论:对于以千枚岩为主、围岩变形大的地层,采用长锚杆大刚度型刚支架,结合网喷纲纤维混凝土等初期支护措施,是控制围岩产生大变形的有效方法之一。

Research on Parameters of Initial Support for Phyllite Stratum at Wushaoling Tunnel

Research purposes:The purposes were to make rational research on initial support and propose the effective support measures according to the big deformation of surrounding rock during excavation of tunnel on phyllite stratum in deep section at Wushaoling Tunnel.Research methods:According to the different contents of phyllite,the trial section was determined and measurement sections were laid out by dynamic design method in combination with the design and construction of phyllite stratum in ridge section at Wushaoling Tunnel on the second line of Lanzhou-Wuwei Railway.The analysis and summary of deformational features of phyllite stratum and design method of initial support under deep buried condition were made according to the site displacement measurement.Research results:The proposed scheme of initial support parameters for phyllitc stratum was presented for reference to design and construction of similar engineering through making research on the deformation of surrounding rock and initial support in excavation of tunnel.Research conclusions:As a result,it was an effective way to control big deformation of surrounding rock by adopting strong rigid support of long anchor and taking initial support measure of net grouting steel fibre concrete to the phyllite stratum with big deformation of surrounding rock.