南京河西地区地铁盾构隧道不均匀沉降分析

依托实测资料,发现南京河西地区某盾构隧道已经形成多个不均匀沉降槽、地面沉降主要发生在软土层、2-4土体地下水位具有呈现正弦函数规律的季节性波动,通过构建的盾构隧道沉降计算公式及典型案例,解释了盾构隧道不均匀沉降是由不均匀分布的下卧软土与外部影响因素共同作用所造成,明确了地下水位的下降对盾构隧道沉降影响最为显著,外部基坑施工影响次之,地表堆载影响较少。

Causes of the Uneven Settlement of Shield Metro Tunnel in Hexi District of Nanjing

Data collected in survey indicate that multiple uneven settling tanks have formed in the shield tunnel in the metro of Hexi district in Nanjing,with the ground settlement mainly occurring in the soft soil in the underlying stratum.In addition,the groundwater level of ②-4 soil presents seasonal fluctuation with the law of sine function.According to the construction of the shield tunnel settlement calculation formula and the typical case,it can be explained that the uneven settlement of the shield tunnel in Hexi district is caused by the interaction between the uneven distribution of the soft soil and the external factors,and it is shown that the decrease of the groundwater level had the most significant influence on the tunnel settlement.The second influencing factor is external foundation pit construction and the last one is the surface load.