摘要
地面出入式盾构隧道(GPST)是一种不需要工作井的新型盾构工法,在国内首次应用于南京地铁。盾构机从地面直接出发,隧道所受荷载与一般隧道有很大区别,传统的惯用法是否适用尚存疑问,因此需要进一步研究隧道的受力变形特性。本文以地面出入式盾构施工过程中出现的负覆土—零覆土—浅覆土工况作为研究对象,建立精细化隧道三维模型,分析隧道在不同覆土厚度工况下的受力变形规律,并获得相应的横向刚度折减系数。同时针对土体侧向土压力系数K0进行参数分析,揭示不同地层条件下隧道收敛变形的变化规律。研究表明,横向刚度折减系数随覆土深度增加而增加,而且随着覆土厚度的增加,变形模式由"横鸭蛋"变为"竖鸭蛋"的临界K0系数值逐渐增大。
Ground penetrating shield technology（ GPST） is a new tunnelling method,which does not require working shaft. It was applied to the Nanjing subway for the first time in China. Since it starts from the ground directly,the loadings acting upon tunnel are different from the traditional ones. Therefore,it is unknown that whether the traditional design methods can be applied or not. It is necessary to carry out a further study on tunnel deformation characteristics. In order to study the behavior of tunnels under the negative,zero and shallow overburdens,a refined 3D FEM model,including detail of tunnel segments,bolts is built for FEM calculation. The deformation of tunnels under different loading conditions and the coefficient of stiffness reduction of sophisticated tunnels relative to inhomogeneous ring are analyzed carefully. The influence of lateral earth pressure coefficient to deformations of tunnels is also analyzed. It is found that the coefficient of stiffness reduction increases with the increasing of overburden depth,and the critical value of K0 at which the deformation model swift from ＂horizontal egg＂to ＂vertical egg＂also increases.
出处
《地下空间与工程学报》
CSCD
北大核心
2016年第2期436-441,共6页
Chinese Journal of Underground Space and Engineering
基金
上海市科委项目(11231202700)
国家自然科学基金(41002097)
关键词
地面出入式盾构
负覆土
三维精细化模型
刚度折减系数
侧向土压力系数
ground penetrating shield technology
negative overburden
refined 3D FEM model
stiffness reduction
lateral earth pressure coefficient
