中文摘要：

双侧壁导坑方法开挖面积小，能够将大断面隧道简化为几个小跨度的导洞隧道，增加了隧道的整体稳定性，是特大断面大跨度公路隧道推荐采用的开挖方法之一。但目前并没有统一标准的双侧壁导坑断面的设计方法，核心土临时支护曲率半径形式的设计具有较大的主观性。而实践表明，临时支护的曲率形式对于核心土和导洞的稳定性影响至关重要。以广州龙头山双洞8车道公路隧道为依托，在相同的边界条件下，通过数值计算、实测数据和现场实例，深入分析核心土临时支护的合理曲率形式。其结果旨在为大断面大跨度公路隧道设计的优化提供借鉴和参考。

英文摘要：

The double pilot tunnel method is one of important excavation means for the super big cross-section and large-span road tunnel. It will reduce the excavation area of tunnel face, decrease the construction difficulty and increase the integral stability of tunnel. However, none unified design criterion of the double pilot tunnel method is available. Especially, it will bring out distinct subjectivity to devise the curvature radius of core-soil temporary support. Furthermore, from practice of tunnel construction, it is found that the curvature radius of core-soil temporary support influences stability of tunnel significantly. Therefore, bases on Longtoushan road tunnel with four traveled lanes in each separated hole, the rational curvature form of core-soil temporary support is discussed and studied mainly with numerical analysis, measured data and illustrations in same botmdary condition. The purpose of the article is to provide reference for design and optimization of the super big cross-section and large-span road tunnels.