软土地层浅覆土大直径盾构施工参数分析

Analysis on construction parameters of large diameter shield under shallow overburden condition in soft clay

依托杭州文一路地下通道北线盾构施工监测数据,对盾构开挖过程中地表最大隆沉变形及施工参数变化情况进行分析研究。结果表明:①监测区段地表最大隆沉值在允许范围以内,说明盾构施工参数控制较好,相应的施工参数可以为类似工程提供参考;②随着盾构掘进深度逐渐增大,切口压力逐渐增大,压力变化梯度小于周围土体重度;③同步注浆总量基本稳定,浆液在盾尾间隙中的流向以自上而下为主;④软土地层中的浅覆土大直径盾构工程较易发生隧道上浮引发的地表隆起,在监测区段管片上浮量和地表隆沉值之间存在一定的相关性。本文分析结果可以为类似工程施工提供参考。

Based on the shield construction monitoring data of the north-line tunnel of Wenyi Road underground passage in Hangzhou,the changes of the maximum ground displacement and the construction parameters during the shield excavation are analyzed.The analysis results show that the maximum ground displacement of the monitoring section is within the allowable range,indicating that the corresponding construction parameters can provide effective reference for similar projects.As the depth of shield excavation gradually increases,the face pressure increases,and the pressure gradient is smaller than the unit weight of the surrounding soil.The total simultaneous grouting volume is basically stable,and the flow direction of the grout in the shield tail gap is from top to bottom.The ground is more prone to heave due to the of the tunnel segment during the large-diameter shield construction under shallow overburden condition in soft clay.There is a certain correlation between the uplift value of the segment and the ground displacement.The analysis results in this paper can provide reference for similar engineering construction.