TBM围岩挤压大变形特性分析与等级划分

Study on the properties of TBM surrounding rock large squeezing deformation and its grading

为了预测评价TBM穿越深部软弱地层时围岩挤压大变形,分析了TBM开挖卸荷围岩挤压大变形力学特性。将TBM围岩挤压大变形定义为TBM开挖后变形速率大、变形量达到TBM扩挖预留的围岩与护盾间的变形间隙,同时收敛速度慢,变形时效性显著的一种变形。指出当围岩挤压变形与开挖半径间的比值大于等于1%且挤压变形与扩挖间隙的比值大于等于1时便产生挤压大变形,并根据这2个指标将TBM围岩挤压变形划分为无挤压变形、轻微挤压变形、中等挤压变形、严重挤压变形和非常严重挤压变形5个等级。

In order to forecast and evaluate the large squeezing deformation of surrounding rock tunnelling by TBM, the mechanical properties of large squeezing deformation has been analyzed. And large squeezing deformation is defined as a kind of deformation in which deforming speed is high, and the amount of the deformation is large and may exceed the overcut gap between the shield and the surround rock mass, with rate of convergence slow, and time dependence significant. If the ratio between surrounding rock convergence deformation and excavation radius is greater than or equal to 1%, and the ratio between convergence deformation and the overcut gap is greater than or equal to 1, large squeezing deformation will occur. And the squeezing deformation is divided by the above two indexes into five grades： no squeezing, minor squeezing, medium squeezing, severe squeezing and extremely severe squeezing.