Abstract:Based on the monitoring data of the Xinjiang Kuyu diversion tunnel,the deformation properties and influential factors of the water-saturated soil tunnel are in-depth analyzed. According to the deformation law of soil tunnel,the process of the effect of deformation after excavation could be divided into three phases:The first phase is the response under the horizontal spatial effect,the second phase is the response under the combination of longitudinal spatial effect and the time effect,the final phase is only influenced by the time effect. The horizontal spatial effect is the main factor leading to roof collapse and landslide during excavation. To reduce the effects of it,the advanced support method or reducing the area in horizontal direction could be adopted;As the longitudinal spatial effect and the time effect dominate the deformation in second phase,a rational separation of them would provides a basis for parameter inversion. In third phase,the time effect primarily is rheological deformation,which appears much more obviously in saturated low liquid limit silt(clay). According to the analysis of the monitoring data which are measured under different classes of surrounding rocks,different buried depths and different supporting intensities,it could indicate that the integration of the silty clay is good,and its main deformation is significantly associated with the buried depth. The deeper the depth is,the more the degree of deformationis. It presents the rheological behavior in some degree simultaneously. During excavation,small-scale landslide is more likely to occur in sand-layered silt and gravel-layered fine sand due to the large water discharge. The deformation is mainly expressed as the looseness of surrounding rock mass and strongly associated with spatial positions of sand layer,while the buried depth of tunnel have no significant influence on it. By using strengthened supporting method and partial excavation method,monitored values of the deformation are mostly small,obvious difference is observed among the deformation properties of supporting structures of the vault and sidewall. The vault can reach stability quickly with little deformation. Plastic area of surrounding rock of sidewall increases as the buried depth in low liquid limit silt(clay),the time effect of stress release is obvious,which manifests as the increasing deformation pressure and large convergence deformation. Steel arch is more significant than the steel grid to limit the deformation of surrounding rock for soil tunnel. Considering the construction cost factor,selection of supporting methods should depend upon different soil properties and different buried depths.
乔春生,管振祥,滕文彦. 饱水黄土隧道变形规律研究[J]. 岩土力学,2003,24 (增2):225-230.(QIAO Chunsheng,GUAN Zhenxiang,TENG Wenyan. A study on deformation of tunnel excavated in saturated loess[J]. Rock and Soil Mechanics,2003,24(Supp.2):225-230.(in Chinese))
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