中文摘要：

石头岗隧道下穿衡昆高速公路,洞身上部为膨胀土,下部为灰岩,呈上软下硬特点,不仅施工风险大,且施工困难。为此采用数值分析手段对上软下硬地层隧道下穿高速公路施工方法进行研究。研究结果表明：上软下硬地层隧道采用上部中隔墙法施工,在降低施工风险、保证施工安全的同时,能加快施工进度,可供类似工程借鉴

英文摘要：

The Shitougang Tunnel crosses under the highway from Hengyang to Kunming.The tunnel was excavated mainly in upper expansive soil and lower limestone.The construction was very hard and adventurous because of the upper soft and lower hard stratum and the highway lyingabove.In this paper,Construction method for railway tunnel crossing under expressway in upper soft and lower hard stratum was studied by numerical analysis method.It is indicated that partition method in the upper soil can not only reduce construction risk,but also accelerate the construction progress