软土地区盾构隧道下穿高速公路施工可行性研究

Feasibility Study of Constructing a Shielded Tunnel Under Passing the Expressway in Soft Soils

随着城市化的持续推进,盾构隧道下穿公路、医院、学校等市政工程的情况越来越多。以华东地区某盾构隧道穿越高速公路为实例,分析了隧道与高速公路的相关位置关系,对场地进行了工程地质调查,查明了地层岩性分布情况、水文地质条件分布情况以及地质构造特征。在此基础上进行了基于Peck公式的理论计算,计算结果可作为分析基础,随后使用MIDAS进行了数值计算,计算结果揭示了隧道开挖后,围岩变形与高速公路、高速公路挡墙的变形规律,并结合前文分析成果,认为盾构隧道的施工对已有高速公路的影响处于可接受范围,研究成果对同类工程起到一定的参考作用。

With the continuous advancement of urbanization,there are more and more cases of shielded tunnel excavations passing through roads,hospitals,schools and other municipal facilities.This paper presents a shielded tunnel in East China to underpass an existing express highway.The relative position between the existing highway and the proposed under passing tunnel.The engineering geological conditions,site soil and rock stratigraphy and properties,hydrological and geological structures were thoroughly investigated.Based on the site-specific information,Peck formula was used to predict the ground response to the tunnel excavation.The analytical results are also compared with the numerical results by MIDAS.The results demonstrate the deformation pattern of the surrounding rock mass as well as the highway and retaining walls after the tunnel excavation.Based on the above analysis results,it is believed that the impact of shielded tunnel construction on the existing expressways is acceptable.