深圳地铁5号线暗挖段下穿老梅子园密集浅基础建筑物,该处地层富水软弱,属于VI级围岩,地层变形不易控制。为确保隧道暗挖施工及地表建筑物安全,采用超前大管棚加固地层、旋喷桩连续隔断墙和地表跟踪注浆等技术措施控制地层变形。其中,管棚加固用以增加地层支护刚度,减小开挖对周围土体的扰动;旋喷桩墙限制隧道开挖的横向影响;地表跟踪注浆改善土层的力学性能,提高土体的压缩强度。地表监测表明,上述措施有效控制了暗挖段开挖过程中的地层变形,使隧道得以顺利通过该区域。 Shenzhen Metro Line 5 under the excavated section of the old plum garden intensive shallow foundation building, where the water is weak and weak, belong to the class VI rock, formation deformation is not easy to control. In order to ensure the tunneling excavation and the safety of the surface buildings, the strata are controlled by technical measures such as advancement of big pipe shed reinforcement stratum, continuous jet grouting piles and surface tracking grouting. Among them, the reinforcement of the pipe shed to increase the stiffness of formation support and reduce the disturbance of excavation on the surrounding soil; jet grouting pile wall to limit the lateral impact of tunnel excavation; surface tracking grouting to improve the mechanical properties of the soil to improve the soil Compressive strength. Surface monitoring shows that the above measures effectively control the formation deformation during the excavation of the undercut section and allow the tunnel to pass through the area smoothly.