城际铁路大直径盾构隧道管片开洞结构受力变形特征分析及结构设计

Analysis of Stress and Deformation Characteristics and Structural Design of the Segment Opening Structure for Intercity Railway Large Diameter Shield Tunnels

为解决大直径盾构隧道开洞结构受力分析等技术难题,确保开洞施工的结构安全,建立隧道硐室开挖过程的三维数值模型,在不同直径盾构隧道、相同开洞尺寸,以及相同直径盾构隧道、不同开洞尺寸工况下,以硐室开挖周围衬砌管片受力变形为研究对象,对大直径盾构管片开洞结构受力变形规律进行研究。研究表明,硐室开挖后,盾构管片变形向硐室一侧发展,由对称变形变为不对称变形,靠近硐室一侧盾构管片变形明显大于另一侧;随着盾构隧道直径增大及开洞尺寸加大,盾构管片受力及变形加大,硐室两侧4 m范围为管片的主要受影响区;改变硐室与盾构的连接形式和开口尺寸,盾构管片的受力也随之改变,通过设计及施工的优化,可以使得盾构管片整体结构受力更合理,结构更安全。

In order to analyze the stress of a large diameter shield tunnel with opening structure,ensure the safety of the structure during the construction,a three-dimensional numerical model of tunnel cavern excavation was established.Different working conditions,such as the different diameter of shield tunnels and hole size were discussed.Taking the lining segment stress around cavern excavation deformation as the research object,the stress deformation law of large diameter shield segment with holes was studied.The results show that,after excavation,the deformation of shield segment develops to one side of the chamber from symmetric deformation to asymmetric deformation,and the deformation of shield segment near the chamber is significantly larger than that of the other side.With the increase of the diameter of shield tunnel and the size of the opening,the force and deformation of shield segment increase.The range of 4 m on both sides of the chamber is the main affected area.The change of the connection form and opening size of the chamber and shield also affects the force of shield segments.Through the optimization of design and construction,the overall structure of shield segment could be more reasonable and safer.