黄土高填方地基沉降变形规律及影响因素分析

为了研究不同侧向约束条件下黄土高填方地基的沉降变形规律及其影响因素,采用有限元软件PLAXIS3D建立了平填型填方地基、贴坡型填方地基以及沟谷型填方地基的数值模型,对高填方地基工后沉降变形规律进行了归纳,并通过灵敏度分析法对黄土高填方地基沉降变形的影响因素进行了敏感性分析; 通过与文献的理论计算结果对比,证明了数值模型的有效性。研究结果表明:不同的侧向约束条件对高填方地基的沉降变形有显著的影响; 侧向约束越强,高填方沉降变形越小,反之亦然,其中平填型填方地基的沉降变形最大,贴坡型填方地基次之,沟谷型填方地基的沉降变形最小,且地形对称分布的沟谷型填方地基变形控制效果优于非对称地形; 随着填土高度和填筑速度的增加,填方地基的工后沉降也会增加; 提高填土的压实度可以显著减小沉降,但改变原位地基处理厚度和沟谷底部宽度对沉降变形的影响相对较小。

Analysis on settlement deformation law and influencing factors of loess high fill foundation

In order to study the settlement deformation law and influencing factors of loess high fill foundation under different lateral constraint conditions, numerical models of flat fill foundation, sticking slope fill foundation and gully fill foundation were established using the finite element software PLAXIS3D. The settlement deformation laws of high fill foundation after construction were summarized, and the sensitivity analysis method was used to analyze the influencing factors of settlement deformation of loess high fill foundation. By comparing the theoretical calculation results in the literature, the effectiveness of the numerical model was proved. The study results show that different lateral constraint conditions have a significant impact on the settlement deformation of high fill foundation. The stronger the lateral constraint, the smaller the settlement deformation of the high fill, and vice versa. Among them, the settlement deformation of the flat fill foundation is the largest, followed by the sticking slope fill foundation, and the settlement deformation of the gully fill foundation is the smallest. The deformation control effect of the gully fill foundation with symmetrical terrain distribution is better than that of asymmetric terrain. As the filling height and filling speed increase, the post construction settlement of the fill foundation will also increase. Improving the compactness of the fill can significantly reduce settlement, but changing the thickness of the in-situ foundation treatment and the width of the valley bottom has a relatively small impact on settlement deformation.