深圳地铁隧道下穿密集建筑施工地层变形控制技术

Ground Deformation Control in Construction of Shenzhen Metro Tunnel under crossing the crowded buildings

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。

The Shenzhen Metro Line 5 is excavated under crossing the Old-Plum Garden with shallow foundation intensive buildings. The surrounding rocks are extremely fractured, and belonging to category-VI. Deformation of soil layers is not easy to control during tunnel excavation. In order to guarantee the safety of construction and surface buildings, leading steel pipeline shed, rotary jet grouting pile and surface tracing compensation grouting are taken during tunnel construction. The leading steel pipeline shed plays a role of increasing the stiffness of the support and reducing the disturbance to the surrounding soil. The ro- tary jet grouting pile limits the lateral deformation of tunnel excavation. The surface tracing compensation grouting improves the mechanical properties of the soil layer and improves the compressive strength of the soil. Strata deformation requirement in the process of excavation of the underground running period has been effectively controlled. It makes subway tunnel running off through the area successfully.