Abstract: Considering the engineering performance of the red-bed soft rock，based on a wide investigation and a technical and economic study of existing freeway project in several provinces in western China red-bed soft rock area，a comprehensive evaluation indicator system was established for cutting and tunnel ahernative assessment with gray relational analysis method． The objective of the research is mainly to get the critical height between cutting and tunnel in order to determine which alternative could be used rationally between cutting and tunne1．The result provides helpful reference for decision-making in freeway design and construction in red-bed soft rock area along a cutting segment．

Key words: red-bed soft rock, freeway, cutting, tunnel, evaluation

摘要： 针对红层软岩的工程性质，利用广泛的调查研究资料，分析了高速公路深挖路段的技术经济影响斟索，构建了 路堑与隧道方案评价的指标体系，并利用灰色关联度作为测度进行综合评价，得到了路堑与隧道相比的合理开挖深 度，为西部红层软岩地区高速公路的设计和施工提供有益参考．

关键词: 红层软岩, 高速公路, 路堑, 隧道, 评价