基于不同本构模型的复杂地层大断面隧道开挖稳定性分析

发布时间：2018-10-31 16:42

【摘要】：多元结构地层中,土体单元触变性高,应力应变路径十分复杂,单一的本构模型不能满足隧道施工变形研究的需要。分析了摩尔库伦、修正剑桥、Druker-Prager和西原正夫等四种本构模型的屈服特性及应力应变关系,通过C++对FLAC软件二次开发,将本构模型程序化。以兰州轨道交通某大断面车站隧道为工程背景,模拟分析四种模型下大断面隧道开挖引起的地表沉降、底板隆起、两帮收剑的变化规律,发现摩尔库伦模型中洛德参数可识别土体单元处于压缩或拉伸状态,能较好地拟合地表沉降规律;修正剑桥模型可追踪岩土体的变形能力和抗剪强度随体积改变而变化的特性,能准确判断隧道直墙的水平位移变化趋势;Druker-Prager模型因考虑中间主应力及静水压力对相邻单元的作用,可反映出隧道内部土体移出后的底板隆起变形特点。以上规律可为复杂多元结构地层中隧道施工变形控制提供参考,从而保证隧道建设的高效与优质。
[Abstract]:In the multi-structural strata, the soil element is highly thixotropic and the stress-strain path is very complex. The single constitutive model can not meet the needs of tunnel construction deformation research. The yield characteristics and stress-strain relationships of four constitutive models, Mohr-Coulomb, modified Cambridge, Druker-Prager and Hirahara, are analyzed. The constitutive model is programmed by the secondary development of FLAC software in C. Taking a large section railway station tunnel of Lanzhou rail transit as the engineering background, this paper simulates and analyzes the variation law of the surface settlement, the uplift of the bottom plate, and the two swords in the excavation of the large-section tunnel under four kinds of models. It is found that the Lod parameters in the Moore Coulomb model can identify that the soil unit is in the state of compression or tension, and can fit the law of surface subsidence well. The modified Cambridge model can track the change of deformation ability and shear strength of rock and soil with the change of volume, and can accurately judge the trend of horizontal displacement of the straight wall of tunnel. Considering the effect of intermediate principal stress and hydrostatic pressure on adjacent elements, the Druker-Prager model can reflect the uplift and deformation characteristics of the bottom plate after the soil is removed from the tunnel. The above rules can provide a reference for the control of tunnel construction deformation in complex multi-structural strata, thus ensuring the high efficiency and high quality of tunnel construction.
【作者单位】：黄淮学院建筑工程学院;中南大学土木工程学院;
【基金】：河南省科技攻关项目(172102310742) 河南省高等学校重点科研项目(16A120015) 黄淮学院校级合格课程建设(1501HK153)
【分类号】：U455.4

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