钻井船拔桩对筒基平台稳定性影响的敏感分析

利用通用的有限元程序ANSYS软件，以渤海8号自升式钻井船和歧口17-2筒型基础平台为对象，采用三维8节点的块体等参元和Drucker-Prager模型，分3步模拟了钻井船桩靴的拔出过程，并在钻井船桩靴与筒型基础筒体之间距离一定的情况下，考虑土性参数的敏感性，就桩靴在拔出过程中对筒型基础平台地基强度以及筒体变位的影响进行了三维有限元分析。分析结果表明，随着筒土相对刚度的减小以及内摩擦角、黏聚力的增大，钻井船拔桩对平台地基承载力的影响逐渐减小；就土性参数中弹性模量、内摩擦角以及黏聚力对筒边地基土体承载力的影响而言，弹性模量和内摩擦角的影响规律更为明显。

Sensitivity analysis of effect on stability of platform with bucket foundation during pile pulling

As Qikou 17-2 platform with bucket foundation and Bohai 8th self-elevating drilling ship for example, it was simulated by three steps for the extracting of pile shoe of drilling ship by using general purpose finite element program ANSYS, using 3D 8-node element and Drucker-Prager elastoplastic stress-strain theory. When the distance between pile shoe and bucket was certain, considering the sensitivity of soil parameters, three-dimensional finite element analysis of the influence on foundation strength of bucket foundation during pile pulling was carried out. It is shown that the effect on ground bearing capacity of platform caused by pile pulling of drilling ship is reducing with the decreasing of relative stiffness and the increasing of internal friction angle and cohesive strength; among natural parameters of foundation soil, as far as the effect on ground bearing capacity of bucket edge soil due to changes of elastic modulus, internal friction angle and cohesive strength is concerned; the effects regularity of the frontal two parts are more obvious than that of the latter one .