砂性土地层盾构隧道开挖面稳定性影响因素分析

Analysis of influencing factors on excavation stability of shield tunnel in sandy soil

盾构隧道在穿越复杂地质区段时多会发生由于支护不够引发的周围土体坍塌或地面隆起等问题,引发支护力不足的诱因很多,本文针对砂性土复杂地层隧道施工前方土体的稳定性影响因素利用Flac 3D展开研究,结果表明:隧道埋深越深对地表扰动越小,土体内摩擦角越大破坏范围越不容易扩散发展至地表,地下水位的高低决定了渗透力所占比重,两者呈正相关,地下水位越高在施工当中越不能忽略渗透力的影响,这些为后续砂性土地层盾构施工提供了积极有效的参考以降低事故发生的概率。

When a shield tunnel passes through a section with complicated geological conditions,it will appear the problems of collapse of surrounding soil or ground heave caused by insufficient supporting force,which is affected by many factors.In this paper,the software Flac 3D is mainly used,the influence factors of the stability of the excavation face of shield tunnel in sandy soil are analyzed,the influence of tunnel depth,soil layer material,tunnel diameter,ground water level on ultimate support stress,soil deformation and the state of soil instability are obtained,so as to guide construction and ensure construction safety.