【摘要】 人工冻结帷幕具有显著的蠕变效应。以上海地铁隧道穿越某正运营车站底板施工段为例,将冻土帷幕当作蠕变材料,隧道内土体及上部结构当作弹性介质,与冻结帷幕外围及结构其它部分相作用的土体当作土弹簧处理,运用大型通用MARC有限元程序,对隧道冻结帷幕开挖与支护的时间效应进行了详细地分析,并与实测数据进行比较,说明该种分析方法是可行的。缩短冻结帷幕暴露时间和采用分台阶开挖方式有利于提高车站底板、冻结帷幕和支护结构的稳定性。更多还原

【Abstract】 The creep property of artificial frozen soil curtain wall is obvious. In the calculating model which is based on the tunnel crossing the bottom plate of using station in Shanghai subway,it is considered that the frozen soil curtain wall is made up of creep media, both soil in tunnel and upper structure are elastic materials, outside soil of the frozen soil curtain wall and structure of station are soil spring. Analysis of time-space effect on excavation and support in frozen soil curtain wall of tunnel is made by 3D FEM- MARC. The calculation results are in good agreement with the test values; so it shows that it is reasonable and creditable to analyze the time-space effects of frozen soil curtain wall by 3D FEM. Moreover, the stabilities of the bottom plate of station, frozen soil curtain wall and the structure of support are increased by decreasing the exposed time of the frozen soil curtain wall and applying the way of step-by-step excavation.更多还原