矿山法铁路隧道复合式衬砌有开挖成形、超欠挖、衬砌厚度控制难等诸多隧道断面尺寸问题及质量“顽疾”。基于高铁双线单洞隧道复合式衬砌设计和施工实践，分析隧道断面尺寸的预设、施工误差、断面测量、欠挖处理、二次衬砌混凝土厚度和方量等方面的问题，按照保证衬砌不欠挖同时严格控制超挖的理念，在隧道断面的尺寸预设和调整、断面测量方法、欠挖处理和初期支护基面修整、拱墙衬砌台车二次衬砌浇筑混凝土方量计算、断面尺寸质量控制等方面提出施工解决对策和建议。

The crosssection size and quality of composite lining of railway tunnel constructed by mining method has many problems such as excavation forming, overbreak and underbreak, and difficult to control lining thickness. The problems of crosssection size including presetting, construction error, section measurement, underbreak treatment, thickness and square quantity of concrete of secondary lining, etc.〖KG-*3〗, are analyzed based on the design and construction practice of composite lining of highspeed railway doubletrack singletube tunnel. Based on the concept of the strict control of overbreak and underbreak of lining, countermeasures and suggestions are put forward from the aspects of tunnel crosssection size presetting and adjustment, section measurement method, underbreak treatment and primary support surface dressing, calculation of concrete volume of secondary lining pouring by arch wall lining trolley, section size quality control measures, etc.