软弱富水地层盾构掘进引起的地表变形控制

Surface deformation induced by shield tunneling in soft soil with rich water and its control measures

以苏州地铁5号线某区间盾构隧道为研究对象,以施工期间掘进参数及隧道地表实测监测数据为依据,分析盾构掘进工程中地质条件、土仓压力、推进速度等因素对地表变形的影响。结果分析表明:盾构掘进面前方一倍洞径处,地表易隆起,地表隆起量随着推进速度、土仓压力、同步注浆压力的增大而增大;随着盾构掘进,地层受施工扰动及水土损失影响,地层开始出现沉降,并不断增大,在距离盾尾两倍洞径位置附近趋于稳定。文中针对盾构在富水砂层、粉土、粉质粘土段掘进存在的问题,提出了地表变形控制措施。

The shield tunneling in a section on Suzhou Metro Line No.5 is taken as an example to analyze the influences of engineering geology,chamber pressure,thrust force,etc.on surface deformation based on shield tunneling parameters and surface monitoring data.The analytical results show that:(1)The surface(one times tunnel diameter ahead of tunnel face)is prone to uplift deformation,and the uplift deformation increase with the increase of thrust force,chamber pressure and synchronous grouting pressure.(2)As shield tunneling,the ground settlement begins and increases due to shield tunneling disturbance and water-soil loss,which becomes stable at area two times tunnel diameter behind shield tail.Finally,countermeasures for surface deformation control are put forward based on the problems encountered during shield tunneling in water-rich sandy stratum,silt stratum and silty clay stratum.