非完全粗糙平板锚旋转安装过程中的丢失埋深研究

吸力贯入平板锚被用于系泊深海浮式结构，实际应用中必须预估平板锚旋转安装过程中的丢失埋深。采用大变形有限元方法探索非完全粗糙平板锚在正常固结黏土中的旋转过程。大变形有限元法通过网格重剖避免平板锚大幅值平动和转动引起的土体单元扭曲。根据平板锚旋转到达的埋深，实时更新“锚-土”界面上的摩擦剪切强度。将数值模拟结果与离心机模型试验进行对比验证，表明高岭土中平板锚表面的粗糙系数约为0.3。平板锚丢失埋深随粗糙系数的减小而增大，但粗糙系数对丢失埋深的影响受平板锚厚度比和拉力偏心比的耦合作用。厚度比和偏心比越小，粗糙系数对丢失埋深的影响越显著。

Losses of embedment of non-rough plate anchors during keying

Suction embedded plate anchors are used to moor large floating structures in deep water.The loss of embedment due to keying of plate anchor during installation needs to be predicted accurately in practical applications.The keying process of frictional anchors in normally consolidated clays is investigated using a large deformation finite element approach.In the large deformation analysis severe distortion of the soil mesh,which is induced by significant translations and rotation of the plate anchor,is avoided by frequent mesh regeneration.The maximum shear strength along the ’anchor-soil’ interface is updated by means of current embedment depth of the anchor.The numerical results are validated by comparisons with the experimental data from centrifuge model tests.It is found that the roughness factor of ’plate anchors-kaolin clay’ interface is valued about 0.3.Totally,the loss of embedment is increased with reduction of roughness factor;however,the loss of embedment depends on the combined influences of anchor roughness,anchor thickness ratio and eccentricity ratio of the pulling force.The influence of anchor roughness on the embedment loss may be enhanced when the thickness ratio and the eccentricity ratio become smaller.