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Abstract 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.
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2015, Vol. 32 
