盾构开挖方式与地层条件适应性研究

The Study on the Accommodation of the Ground Condition and the Form of the Shield Tunnel Face

盾构施工的土层条件及掘进环境等越来越复杂多样,在复杂的地层开挖如何根据不同地层条件高效率地利用盾构施工技术进行开挖,成了现今盾构施工界普遍关注的问题。采用三维有限差分数值分析方法,针对土压平衡式盾构在砂性土地层及风化岩地层掘进施工中,开挖面支护压力不足所引起的极限平衡破坏状态进行了分析研究,探讨了地层条件对盾构开挖方式的影响,得出砂土不推荐使用敞开式开挖,而在风化岩地层中开挖时,为了提高施工效率,在一定条件下可以采用敞开式开挖。

The earth condition around the shield tunnel is more and more complex.It has been a popular problem that people make better use of the technology of the shield tunnel according to the different ground conditions.A three dimensional fast Lagrangian differential finite element method which could reflect the large strain behavior of material was employed to simulate the deformation and failure of excavated face.Based on the numerical analysis,some insights were given and discussed.It is concluded that the mode of open-face shield should not be operated in sand.Some condition in weathered rock could be excavated by the open-face shield.