黄土隧道地基湿陷变形评价方法探讨

发布时间：2018-04-05 07:25

本文选题：土力学　切入点：黄土隧道　出处：《岩石力学与工程学报》2017年05期

【摘要】：隧道穿越自重湿陷性黄土地层时,可能遭受浸水作用下地基湿陷变形的附加作用而产生结构破坏。针对隧道衬砌结构的湿陷性黄土地基,结合隧道围岩及地基的自重湿陷变形特征,首先,提出浅埋隧道围岩压力、衬砌结构自重荷载构成基底压力和隧道两侧基底面分布土层自重共同作用下地基土的附加应力计算方法,以及考虑地基土自重应力的湿陷压缩应力计算方法。其次,在基本物性与构度、构度与结构压缩屈服应力、孔隙比和初始孔隙比比值与压缩应力和结构压缩屈服应力比值关系的基础上,建立自重湿陷系数和湿陷系数的计算方法。依据大厚度自重湿陷黄土场地不同埋深范围黄土具有不同自重湿陷系数门槛值的特征,得到了场地的自重湿陷变形和隧道地基的湿陷变形的计算方法。最后,通过数值计算分析,模拟隧道地基湿陷变形不同沉降差作用下衬砌结构应力场和塑性域发展,随着不均匀湿陷变形的增加,隧道衬砌结构塑性区范围不断增大,并结合铁路路基沉降控制标准,建议隧道地基湿陷变形0~5 cm为一级、5~10 cm为二级、大于10 cm为三级。
[Abstract]:When the tunnel passes through the self-gravity collapsible loess stratum, it may be subjected to the additional action of subgrade collapsing deformation under the action of soaking, which may result in structural damage.Aiming at the collapsible loess foundation of tunnel lining structure, combined with the deformation characteristics of tunnel surrounding rock and ground, firstly, the pressure of shallow tunnel surrounding rock is put forward.The calculation method of the additional stress of the foundation soil under the combined action of the load of the lining structure and the distributed soil layer on both sides of the tunnel and the method of calculating the collapsing compression stress of the foundation soil considering the gravity stress of the foundation soil are presented.Secondly, on the basis of the relations between the basic physical properties and the structure, the ratio of the structure and the compressive yield stress, the ratio of the void ratio and the initial void ratio to the compression stress and the compressive yield stress, the calculation method of the self-gravity collapsibility coefficient and the collapsibility coefficient is established.According to the characteristic that loess has different threshold value of deadweight collapsibility coefficient in different buried depth of loess site with large thickness, the calculation method of self-weight collapsing deformation of site and tunnel foundation is obtained.Finally, through numerical calculation and analysis, the stress field and plastic domain development of lining structure under different settlement difference of tunnel foundation collapsing deformation are simulated. With the increase of uneven collapsing deformation, the plastic zone range of tunnel lining structure increases continuously.Combined with the control standard of railway subgrade settlement, it is suggested that the subgrade deformation of tunnel foundation should be 0 ~ 5 cm, 1 ~ 5 ~ 10 cm, 2 ~ 2, > 10 cm, 3 ~ 3, respectively.
【作者单位】：西安理工大学岩土工程研究所;西安理工大学陕西省黄土力学与工程重点实验室;
【基金】：国家自然科学基金资助项目(41272320,11572245)~~
【分类号】：U452.11

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