基于土体的大变形分析钻井船插桩对邻近桩的影响

自升式钻井船插桩对邻近平台桩基础的影响主要体现为插桩导致的土体大变形会使邻近平台桩基础受到附加水平荷载。当钻井船插桩时的桩靴边缘与邻近平台桩外缘之间间距小于桩靴直径时,就需要定量评价钻井船插桩对邻近平台桩的影响程度。基于分析被动桩响应的两段法原理,通过开发ABAQUS中分析材料大变形的网格重新划分算法与相应的计算结果后处理方法,CEL计算结果的后处理方法,形成了求解钻井船在自由场地插桩时周围土体极大变形的有限元算法;进而,依据计算出的自由场地土体位移,采用增量有限差分方法求解非线性地基梁控制方程,即可获得钻井船插桩时的邻近桩桩身响应。以上形成了一种能够定量分析钻井船插桩对邻近桩影响的两段法。利用此方法预测已有的离心模型试验结果,获得了与实测结果基本吻合的预测结果。这表明建立的用于分析钻井船插桩对邻近桩影响的两段法是可行的。

Effects of spudcan penetration on adjacent piles based on large deformation of soils

The effects of spudcan penetration on adjacent piles are mainly embodied in the additional lateral loads induced by large deformation of soils. It is a common practice to quantitively evaluate the effects when the edge-to-edge clearance between the spudcan and the pile is less than the spudcan diameter. The conventional two-stage passive pile analysis method is utilized to investigate the process. Analysis continuation after the mesh replacement (mesh-to-mesh) technique is improved and post-processed, and CEL technique is post-processed to calculate the soil displacement during free-field spudcan penetration. Then by considering the nonlinear beam foundation model and p-y data, the bending moments of pile during spudcan penetration can be calculated by means of the incremental finite difference method based on the free-field soil displacement. Thus a two-stage method to analyze the effects of spudcan penetration on adjacent piles can be formed. Good agreement between the calculated and measured results is found compared with the available centrifuge tests by which the efficacy of the proposed method can be proved.