The phenomenon of the soil plug usually rising inside the suction foundations during suction penetration was quantitatively described and predicted. The formation process of the soil plug was simulated and calculated by DEM （discrete element method） model. The seepage flow, the self-weight of soil, the friction on the chamber wall as well as the suction inside the chamber are considered as the main external forces in the process. The results are compared with a set of laboratory model tests performed by using three soil types （sand, silty clay and clay） in the Bohai Sea area. The heights of soil plug from numerical estimations are lower than those from model test results, mainly because the suction pressure and friction resistance are applied in an ideal way under the numerical simulation.
筒型基础沉放施工中,随着入土深度的增加,筒体所受的侧摩阻力越大,当达到一定程度时,将导致基础无法继续下沉。为了避免这种情况的发生,在实际的施工中可以在锚体上设置剪土环以减小侧摩阻力的影响。论文针对海上吸力锚基础这一新型海洋平台基础形式研究中面临的吸力锚负压沉贯下沉中设置剪土环及剪土环对其渗流场的影响这一问题,通过对吸力锚渗流场的有限元分析,运用有限元软件AN SY S对锚体周围土体渗流场进行建模分析,利用有限元计算的结果来分析剪土环对渗流场的影响。
The soil plug phenomenon involving the rising of the surface soil inside the bucket chamber under the suction pressure and seepage forces was simulated and calculated by deformable discrete element method (DDEM) models. The seepage forces, the effective gravity of soil, the friction on the chamber wall and the suction inside the chamber are considered as the main external forces of DDEM specimen. Three typical types of soil (silty clay, silt and sand) in the Bohai Sea are set as the main environmental conditions in the formation process of soil plug. It is found that the heights of soil plug simulated by DDEM models are 161.85 mm in silty clay, 125.22 mm in silt and 167.56 mm in sand, which are close to model test results and higher than those estimated by discrete element method (DEM). DDEM is an effective method to estimate and predict the heights of soil plug before suction penetration of bucket foundations on site.
