超大直径盾构隧道正交下穿对既有地铁隧道影响分析

Influence of super-large diameter shield tunnel perpendicular undercrossing on existing operating tunnel

为研究超大直径盾构隧道正交下穿对既有地铁隧道的影响,基于深圳市春风隧道工程施工下穿地铁1号线工程实例,采用数值模拟和现场实测的方法综合分析超大直径泥水平衡盾构正交下穿过程地表和既有隧道沉降变化。结果表明:数值分析显示,加固工况下盾构隧道穿越段地表最大沉降量为3.37mm,地铁站结构最大沉降量为1.12mm,均小于未加固工况下的沉降值。现场采取掘进控制为主、辅之以洞内注浆加固措施后,春风隧道实际穿越地铁1号线过程地表最大沉降量为2.93mm,隧道结构最大沉降量为1.05mm。现场实测结果与数值模拟预测结果高度吻合,且满足安全评价提出的控制指标及相关规范要求。研究结果对于超大直径盾构隧道下穿既有隧道沉降变形控制及安全风险管控具有参考意义。

The under-passing of super-large diameter shield tunnel has a significant impact on the stability of the existing operating tunnel.In this paper,a case study is conducted on Chunfeng tunnel(15.8m in diameter)perpendicularly undercrossing the existing tunnel of Shenzhen metro line 1,and the settlement changes of the ground surface and the operating tunnel are analyzed by using the method of numerical simulation and field measurement.The results show that under the reinforcement condition,the maximum settlement of ground and the operating tunnel structure are 3.37mm and 1.12mm,respectively,smaller than those under the unreinforced condition.After taking the tunneling parameter control as the main measure,supplemented by grouting reinforcement during shield tunneling,the maximum settlement of the ground and the tunnel structure is 2.93mm and 1.05mm,respectively.The field measured results of settlement are highly consistent with the predicted results based on numerical simulation and meet the control indicators proposed by the safety assessment and relevant specifications.The research results have certain significance for the guidance of super-large diameter shield tunnel safely undercrossing the existing tunnel.