整体冲刷作用下吸力式桶形基础稳定性分析

Stability Analysis of Suction Bucket Foundation Under General Scour Effect

吸力式桶形基础在正常工作过程中将始终受到波流的冲刷作用,海床的剧烈运动使其冲刷范围甚至会达到整体冲刷的情形,严重时将导致整个海上工程失稳破坏,带来巨大的经济损失。本文开展了砂土中整体冲刷作用对吸力式桶形基础稳定性影响的模型试验,分析了冲刷作用对基础位移模式、桶顶位移和转动点的影响规律。研究发现:整体冲刷作用不影响基础位移模式变化规律,在波浪循环荷载作用下基础位移模式始终表现为随着循环次数的增加从平动发展为转动;基础周围若存在整体冲刷将严重影响基础稳定性,冲刷深度对桶顶位移影响极大,基础桶顶最大位移与冲刷深度成平方关系;冲刷深度对于转动点位置影响较小,随着冲刷深度增加,转动点位置仅略微下移。

When suction bucket foundation is in the working process,it is always under the scour effect which induced by the wave and current.General scour can even occurs because of the rough movement of the seabed.It will lead to instability and damage of the whole offshore engineering and then cause huge economic losses.Consequently,a model test was carried out to investigate the general scour effect on the stability of suction bucket foundation.The motion pattern,bucket top displacement and the rotation point position were analyzed.The results indicated that the motion pattern was not affected by general scour and always changed from translation to rotation with the increase of cyclic times under wave loads.General scour seriously affect the stability of the foundation.The scour depth had a great influence on the bucket top displacement.The maximum bucket top displacement was equal to a scour depty square.The position of rotation point,however,was little affected by scour depth.And the position of rotation point moved down slightly with the increase of scouring depth.