吸力贯入式板锚锚眼位置优化的宏单元分析

Macro-element analysis of optimizing the position of padeye for SEPLA

为确定吸力贯入式板锚锚眼最优位置,建立了预测SEPLA旋转上拔过程的宏单元模型,在Matlab下编制了相应的计算程序,分析了板锚锚眼切向偏心、法向偏心和泥面角对SEPLA的埋深损失、承载力及板锚旋转角的影响.结果表明:随着切向偏心比增加,板锚的旋转角和锚眼角近似线性增大,板锚埋深损失先减小后增加;随着切向偏心比增加,锚链作用线与板锚平面之间的夹角逐渐减小,这不利于发挥板锚的承载作用.随着法向偏心比增加,旋转角减小,且减小速率逐渐趋缓,当法向偏心比为0.6时,再增加法向偏心比,旋转角基本不变,锚链拉力方向与板锚近似垂直,有利于板锚承载;随着法向偏心比增加,板锚承载力系数增加,但增加速率逐渐趋缓.当板锚的法向偏心比为0.6后,承载力系数基本不再增长;随着泥面角增加,板锚的埋深损失、旋转角和锚眼角都增加,但锚链作用线与板锚的夹角不变,板锚的承载能力也基本不变;SEPLA板锚的切向偏心比不宜超过0.1~0.2,法向偏心比宜为0.6,泥面角宜为30°.

In order to optimize the position of padeye for suction embedded plate anchor(SEPLA), a macro element model to predict the rotation and uplift of SEPLA is presented. The corresponding code was developed in Matlab. The effects of the normal and tangential offset, mudline angle on the loss of embedment, bearing capacity and rotation of the SEPLA are analyzed using the code, and our main conclusions include: with increasing the tangential offset ratio, the rotation angle of the fluke and the padeye angle both are linear increasing. The loss of embedment increases at first, then decreases. With increasing the tangential offset ratio, the angle between the chain direction and the plane of anchor decreases, which will reduce the bearing capacity of anchor. With increasing the normal offset ratio, the rotation angle decreases and stabilizes. After the normal offset ratio arrives at 0.6, the rotation angle basically is constant. The chain direction is approximately normal to the plane of anchor, which benefits the bearing capacity of anchor. Increasing the normal offset ratio benefits the bearing capacity coefficient towards stabilized value. After the normal offset ratio arrives at 0.6, the bearing capacity coefficient approximately is constant. With increasing mudline angle, the loss of embedment, rotation angle and padeye angle all increase. However the angle between the chain direction and the plane of anchor and the bearing capacity are approximately constant. The tangential offset ratio less than between 0.1 and 0.2, the normal offset ratio of 0.6 and the mudline angle of 30° for SEPLA are recommended.