大断面矩形顶管隧道施工引起的地面沉降分析

针对郑州市下穿中州大道的双线矩形顶管隧道,通过现场实测对双线隧道施工过程中地面沉降变化规律和分布特征进行分析。研究结果表明:大、小矩形顶管隧道施工对地面沉降的影响范围分别为大、小顶管隧道宽度的1. 4倍和1. 5倍,对刀盘前方土体的扰动范围分别为大、小顶管隧道宽度的1. 3倍和3. 0倍;管节脱离矩形顶管机尾7 d后地面沉降趋于稳定;倒锥形壳体锥度设置过大、前后壳铰接处漏浆和土仓压力设置不合理是诱发地面沉降的关键因素。

Analysis of Ground Subsidence Caused by Construction of Large Section Rectangular Pipe Jacking Tunnel

According to the double-line rectangular pipe jacking tunnel under-crossing Zhongzhou Avenue in Zhengzhou,the variation law and distribution characteristics of ground subsidence during the construction of double-line tunnel were analyzed by f ield measurement.The results show that the inf luence range of large and small rectangular pipe jacking tunnels construction on ground subsidence is 1.4 times and 1.5 times of the width of large and small pipe jacking tunnels respectively,the disturbance range of soil in front of cutter head is 1.3 times and 3.0 times of the width of large and small pipe jacking tunnel respectively,the ground subsidence tends to be stable seven days after the pipe segment is separated from the rectangular pipe jacking tail.The key factors inducing ground subsidence are too large taper setting of inverted conical shell,leakage of slurry at hinges of front and rear shells and unreasonable setting of earth pressure.