盾构不同穿越形式引起既有盾构隧道变形机理分析

Analysis of Displacement of Existing Shield Tunnel due to Different Crossing Patterns

新建盾构隧道穿越会对临近既有盾构隧道产生不利影响。文章考虑盾构施工因素、土体损失及周围土体的卸载回弹等,分析了新建隧道上穿越和下穿越这两种穿越方式对既有盾构隧道产生变形的影响机理,并对现有7种理论计算方法进行了综述。收集了国内5项上穿既有隧道和9项下穿既有隧道的工程实例,对实测数据和工程中用到的加固控制措施进行统计分析。研究结果表明:当新建隧道上穿越既有隧道时,既有隧道会产生向上隆起的趋势;当新建隧道下穿越既有隧道时,既有隧道会产生向下沉降的趋势;实测数据的统计分析结果和理论方法计算结果均验证了机理分析结果的可靠性。

The new shield tunnel,which is under approaching construction,will adversely affect the adjacent existing shield tunnel.The mechanism of the deformation of the existing shield tunnel is analyzed from the aspects of construction,ground loss and unloading rebound of the surrounding soil in this paper.It summarizes the seven theoretical calculation methods by analyzing the influence mechanism of the deformation of existing shield tunnels which is resulted by the newly-built shield tunnels in two kinds of crossing modes.In this paper,it collected five engineering examples of the newly-built shield tunnels which are above-crossing the existing tunnels and nine engineering examples of the newly-built shield tunnels which are below-crossing the existing tunnels,and analyzed the measured data and the reinforcement control measures used in the projects.The results show that the existing tunnel have a trend of uplift when the new shield tunnel crosses above it,and a trend of subsidence when the new shield tunnel passes beneath it.The result of the statistical analysis of the measured data and theoretical calculation verify the reliability of the mechanism analysis.