机械预切槽法开挖软土隧道地层变形研究

软土中的机械预切槽法是超前支护的一种，在预筑拱的保护下可以安全高效地开挖隧道。在隧道力学和弹塑性理论的基础上，利用自行开发的三维程序，分析了机械预切槽法与常规全断面法开挖隧道时引起的地层变形。计算结果显示：机械预切槽法形成的预支护作用在控制地层变形方面较常规全断面法具有明显的优势，预切槽法可以减少隧道施工对地层变形的影响范围和影响程度，可以用于对地表沉降控制较严格地区的隧道施工。

A study of ground deformation when excavating tunnel in soil by Mechanical pre-cutting method

The Mechanical pre-cutting method used in soft ground is a kind of preparative support, it allows tunnel excavation work to be conducted efficiently under the safe pre-lining. In this paper, a 3D FEM program based on tunnel mechanics and elastic-plastic theory is developed to analyze the ground deformation when excavating tunnel by Mechanical pre-cutting method and the conventional full section method. The result show: the Mechanical pre-cutting method has evident advantage in controlling ground deformation compare to the conventional full face method because of its preparative support function. The pre-cutting method can reduce the ground deformation range and extent in tunnel construction, so it can be used in tunnel construction in the district where the strict limitations on surface settlement is set.