基于不同本构模型黄河厚冲积层基坑开挖结构变形分析

发布时间：2018-07-25 14:11

【摘要】：采用理论分析结合现场实测数据,以黄河厚冲积层地质条件下某深大基坑开挖为实例,利用修正剑桥、西原正夫及改进的西原正夫等5种本构模型,通过FLAC仿真软件构建3D数值模型,分析基坑开挖引起的围护桩变形规律、墙后土体沉降变化特征、坑底土体上移趋势及抗浮桩侧摩阻力分布特点。结果表明:西原正夫本构模型可描述粘土体的蠕变变形,能准确追踪围护桩侧向位移;修正剑桥模型通过自动调整自身抗剪强度和弹性模量等参数,可给出墙后土体沉降的正确规律;摩尔库伦模型拟合得到的坑底土体上移曲线与现场实测数据较吻合;在改进的西原正夫及修正剑桥模型下,计算得到的抗浮桩侧摩阻力最为保守。上述规律可供预测基坑后续运营期间的结构变形、延长结构的服役年限参考。
[Abstract]:Taking the excavation of a deep and large foundation pit under the geological condition of the thick alluvial layer of the Yellow River as an example, five kinds of constitutive models, such as modified Cambridge, Xihara Zhengfu and improved Xihara Zhengfu, are used in this paper. A 3D numerical model was constructed by using FLAC software to analyze the deformation law of retaining pile caused by foundation pit excavation, the characteristics of soil settlement behind the wall, the upward trend of soil mass at the bottom of the pit and the distribution of lateral friction of anti-floating pile. The results show that the constitutive model can describe the creep deformation of clay body and track the lateral displacement of retaining pile accurately, and the modified Cambridge model can automatically adjust the parameters such as shear strength and elastic modulus. It is possible to give the correct law of soil settlement behind the wall, and the curve of soil movement at the bottom of the pit obtained by Moore Coulomb model is in good agreement with the measured data on the spot. Under the improved Xihara Zhengfu model and the modified Cambridge model, The lateral friction of anti-floating pile is the most conservative. The above rules can be used as a reference for predicting the structural deformation and prolonging the service life of the structure during the subsequent operation of the foundation pit.
【作者单位】：济南轨道交通集团有限公司;山东科技大学土木工程与建筑学院;
【基金】：山东省自然科学基金项目(ZR2014EEM029);山东省自然科学基金项目(ZR2014EEQ028) 山东省住房和城乡建设厅项目(KY053) 住房城乡建设部项目(2015-K5-004)资助
【分类号】：TU473

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