软土地层大断面矩形隧道结构施工力学行为监测与分析  

Monitoring and Analysis of Construction Mechanics Behavior of Rectangular Tunnel Structure with Large Cross-section in Soft Soil Stratum

作　　者：赵辉 

机构地区：[1]中铁四局集团城市轨道交通工程分公司,安徽合肥230023

出　　处：《隧道建设》2017年第A01期46-52,共7页Tunnel Construction

摘　　要：为确保软土地层大断面矩形下穿隧道施工时的安全,以昆明轨道交通3号线区间浅埋暗挖隧道为依托,采用中导洞法,将全断面分成6个导洞按照先中间后两侧、先上面后下面的顺序施工,并采用现场监测和理论分析的方法对隧道支护结构受力进行全过程监控与分析。监测分析结果表明:在矩形隧道顶部与侧面设置超长大管棚条件下,隧道初期支护内力变化较小,因受不同导洞开挖扰动影响,隧道结构底部出现受拉现象,导洞(2)(中下导洞)、导洞(4)(左下导洞)和导洞(5)(右上导洞)对整体结构安全起决定性作用,需要重点监控;最大围岩接触应力出现在导洞(4)(左下导洞)底部,隧道4个角的围岩应力明显大于其他部位,需要加强隧道底部基础注浆,以提高地基承载力;临时支护应力受不同导洞开挖影响出现明显的波动,很好地反映各导洞施工过程中围岩应力释放的特征。Based on the running tunnel（ Jinmasi-Taipingcun） on Kunming Metro line No. 3,the intermediate pilot method is adopted for the large cross-section rectangular tunnel in soft soil stratum. The mechanical characteristics of tunnel structure are monitored and analyzed by field monitoring method combining with construction theory during tunnel construction. The results show that the internal force of tunnel primary support is in a stable range under the condition of long pipe roofing grouting at roof and bilateral sides. And the axial force of primary support is in a tension state at the bottom of pilot tunnel due to the excavation disturbance of different pilot tunnels,especially the construction process management should be strengthened during the construction of the second,fourth and fifth pilot tunnel. The maximum stress between surrounding rock and structure appears at the bottom of pilot tunnel. And the stresses of four corners of rectangular structure are obviously more than those of other parts of tunnel structure,which shows that the grouting measure should be adopted so as to improve the bearing capacity of tunnel foundation. Based on the analysis of the stress change law of temporary support,the stress of temporary structure appears in an up-down change state caused by the construction process of different pilot tunnels,which reflects the stress releasing characteristics of surrounding rock for all pilot tunnels. The results can provide reference for the design,construction and monitoring of shallow-buried rectangular tunnel in soft soil stratum.

关 键 词：软土地层 大断面矩形隧道 中导洞法 施工力学 监控量测 

分 类 号：U456[建筑科学—桥梁与隧道工程]