长沙地铁富水软弱地层盾构下穿京广铁路风险分析与控制研究

长沙地铁1号线区间盾构下穿京广铁路段穿越富水软弱地层,施工风险高。针对具体地质与环境条件进行风险分析与控制研究,对盾构下穿铁路施工风险进行系统分析,阐述其风险因素及造成的危害,为有效规避下穿京广铁路风险,提出了旋喷桩加固+"横抬纵挑法"的风险控制措施。结合现场施工与监测情况,探讨京广铁路路基沉降的变形规律,对京广铁路的安全进行评价。实践证明,风险控制措施效果良好,可供类似工程参考。

Construction Risk Analysis and Control Measures for a Changsha Metro's Shield Tunnel Crossing below Existing Beijing-Guangzhou Railway in Water-rich Soft Soil Stratum

There was high construction risk in the water-rich soft soil stratum where a shield tunnel of Changsha Metro line 1 crossed below the existing Beijing-Guangzhou Railway. For this reason,this paper analyzed the construction risk and researched relevant control measures in combination with the specific geological and environmental conditions. And then emphatically and systematically,this paper analyzed the risk of shield tunneling below the existing railway,and expounded the risk factors and the harms caused by them. Furthermore,in order to effectively avoid the risk caused by shield tunneling below the existing Beijing-Guangzhou Railway,this paper proposed a set of risk control measures: strengthening by chemical churning piles and supporting by longitudinal and transverse beams. In addition,combining with field construction and monitoring data, this paper discussed the characteristics of subgrade deformation of the Beijing-Guangzhou Railway,and carried out safety evaluation for this railway.Practice shows that this set of risk control measures is suitable and effective and can serve as a reference for similar projects.