论文部分内容阅读
以长春地区土岩复合地层条件下地铁自由大路车站工程为依托,对地铁车站PBA法导洞施工引起地表沉降规律进行了分析。研究结果表明:(1)车站主体双层暗挖导洞施工引起的地表累计沉降量占车站施工最终沉降量的一半以上,约53.46%,地表沉降槽曲线为“单峰”形态,横向影响范围约50 m左右。(2)导洞施工诱发地表沉降分为初期沉降、快速沉降及沉降收敛3个阶段,初期阶段沉降4 mm左右,占14.81%,快速阶段沉降20 mm左右,占74.07%,收敛阶段沉降3 mm左右,占11.11%,隧道施工过程须重点监测掌子面靠近监测断面6 m与远离监测断面15 m的施工段。(3)开挖顺序与开挖进尺对地表沉降影响较大,选择先上后下,先边洞后中洞的开挖顺序最为合适,开挖进尺控制在0.1L~0.14L(L为洞跨)为宜。
Based on the project of Freeway Subway Station under the conditions of earth-rock compound strata in Changchun area, the ground subsidence regularities caused by the PBA pilot tunnel construction in subway station are analyzed. The results show that: (1) The cumulative total surface subsidence caused by the construction of double-layer tunneling at the station main site accounts for more than half of the final settlement of the station construction, accounting for about 53.46% of the total. The curve of the surface subsidence tank is in the form of “single peak” The influence range is about 50 m. (2) Surface subsidence induced by pilot tunnel construction is divided into three phases: initial settlement, rapid settlement and settlement convergence. The initial settlement is about 4 mm, accounting for 14.81%, the rapid settlement is about 20 mm, accounting for 74.07% and the convergence is 3 mm , Accounting for 11.11%. The construction process of the tunnel should focus on monitoring the construction section where the face of the tunnel is close to the monitoring section 6 m and away from the monitoring section 15 m. (3) Excavation sequence and excavation footage have a great influence on surface subsidence. After choosing the first and the second, the excavation sequence of the middle hole after the first one is the most appropriate, and the excavation footage is controlled at 0.1L ~ 0.14L (L is the hole Cross) is appropriate.