Double primary support structures could effectively solve the problem of large deformation of surrounding rock for soft rock tunnels. However, the mechanical behavior of this new support structure is still incomplete, and the design method should be revised. Based on the theory of energy conversion, this paper analyzes the support characteristic curve of double primary support and puts forward the dynamic design method of double primary support. Considering that the secondary lining can be set after monitoring the deformation amount and deformation rate of the first primary support, its support parameters can be dynamically adjusted according to the actual situation. By applying the double primary support design method in the Maoxian tunnel of Chenglan Railway, the field monitoring results show that the double primary support has a significant effect on the energy release of surrounding rocks, greatly reducing the load acting on the secondary lining and ensuring the safety and reliability of the tunnel structure.

中文翻译：

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高地应力大变形下软岩隧道双主支护力学特性研究

双主支撑结构可以有效解决软岩隧道围岩大变形的问题。但是，这种新的支撑结构的机械性能仍不完善，应修改设计方法。基于能量转换理论，分析了双主支撑的支护特性曲线，提出了双主支撑的动态设计方法。考虑到可以在监测第一主支撑的变形量和变形率后设置第二衬砌，可以根据实际情况动态调整其支撑参数。通过在城兰铁路茂县隧道采用双主支护设计方法，