研究目的:大断面黄土隧道开挖可采用双侧壁导坑法、CRD法、台阶法等，本文依托郑州至西安高速铁路大断面黄土隧道工程实例,通过对三种常用工法的理论分析,并结合现场初期支护下沉收敛、地表沉降的监测,对比分析各种工法的优缺点,提出适用于高速铁路大断面黄土隧道安全快速的开挖方法。
研究结论:（1)在三台阶七步法、CRD法及双侧壁导坑法中,初期支护在施作二次衬砌前的安全系数分别为1.3、1.4、2.6, CRD法及双侧壁导坑法临时支护安全系数最小值为1.2、1.9，均能保证施工阶段的安全； (2)地表沉降值和黄土性质关联性更强,采用三台阶七步法和CRD法开挖,地表沉降值均在10 cm以上,双侧壁导坑法可将地表沉降值控制在5 cm以内；（3)高速铁路大断面黄土隧道无特殊情况下宜采用三台阶七步法开挖；（4)本研究成果可为类似断面工程的施工提供借鉴。
Research purposes ： The large section loess tunnel excavation method can use double side heading method， CRD method and steps method， etc. Taking loess tunnel project of Zhengzhou to Xilan high - speed railway as an example，based on theoretical analysis of three kinds of common construction methods，and combined with the primary support sinking of convergence，the surface subsidence monitoring， this paper compared and analyzed the advantages and disadvantages of various methods，proposed the safe and rapid excavation method suitable for large section loess tunnel of high - speed railway.
Research conclusions: ( 1 ) The safety coefficients of primary support of three steps and seven steps，CRD and double side heading method in applied in front of the secondary lining are 1.3，1. 4 and 2. 6，the temporary support minimum safety coefficients of CRD and double side heading tunnel method are 1. 2 and 1.9，and all can meet the construction safety. (2)The correlation between surface subsidence value and the loess nature is stronger，using three steps and seven steps and CRD excavation method surface subsidence value is more than 10 cm，double side heading method can control the surface subsidence value within 5 cm. (3 ) It is suitable to use three steps and seven steps excavation method in the large section loess tunnel of high - speed railway in the absence of any special. (4) The research result can provide reference for similar projects.
PDF(982 KB)
