苏州街站后停车线区间横通道施工工法

Construction Method of Cross Passage of Parking Line Section Behind Suzhou Street Metro Station

北京地铁16号线苏州街站后停车线区间横通道兼作盾构机接收、平移、吊出通道,开挖断面较大。该盾构接收施工通道原设计方案为CRD法施工,在竖井开挖过程中发现该区域地下水位高,降水施工极为困难。为确保盾构接收通道施工安全,从工期、沉降等方面对CRD法和洞桩法2种施工方案采用有限元数值模拟对比分析。结果显示:洞桩法地表沉降值远小于CRD法;导洞开挖、扣拱及中板以上结构未进入地下水标高范围内,不存在地下水干扰,工期及风险可控;扣拱及负一层结构完成后,横通道受力框架已形成,负二层土方开挖及结构施工在边桩支护下,虽局部存在地下水,但风险可控。故将设计方案变更为洞桩法。实施结果证实洞桩法用于富水卵石地层暗挖地下工程效果比较显著。

The cross passage of parking line section behind Suzhou street metro station in Beijing subway line 16 is used as the channel for shield machine receiving,translation and hanging out and has a large excavation section.The original design scheme for shield receiving cross passage construction was CRD method.During the excavation of the shaft,it was found that the underground water level of this area was high and the construction of precipitation was extremely difficult.In order to ensure the construction safety of shield receiving channel,the finite element numerical simulation method was used to compare and analyze two kinds of construction schemes which are CRD method and hole pile method in terms of construction period and settlement.The results show that the surface settlement value of the hole pile method is far less than the one of CRD method,pilot tunnel excavation and construction structure above the arch and medium plate is not within the range of groundwater level,there is no interference of groundwater,the time limit for a project and risk can be controlled,after the completion of arch and construction structure of first basement,cross passage stress framework has been formed,the earthwork excavation and construction structure of second basement under the edge pile support although has the local existence of groundwater but the risk is in control.The design scheme was changed to hole pile construction method,and the experiment results confirme that the hole pile construction method applied in underground excavation engineering of water-rich pebble stratum has a significant effect.