波浪荷载作用下滩海人工岛工程稳定性评价

波浪荷载是海洋地基土受到的最频繁和最严峻的周期性动荷载。通常坐落在软土地基上的海工结构物的破坏并不是由于其结构本身的破坏,而是由于在波浪等往复荷载的作用,土层受到扰动,承载力降低,致使地基沉降过大,从而导致构筑物失稳。以滩海人工岛构筑物为例,依据前人研究成果,并结合研究区域实际情况,根据三个特征水位(设计高水位、设计低水位及百年一遇高潮位),选取不同强度折减系数来考虑波浪荷载对海床的不同弱化程度。文中建立人工岛评价模型,采用有限单元法,分析了不同水位及对应的波浪荷载作用下的人工岛稳定性现状、竖向位移和水平位移。结果表明考虑波浪荷载作用时,人工岛的稳定性系数大幅降低;而在设计低水位条件下,当波浪弱化作用导致折减后的海床强度为40%时,人工岛稳定性系数为1.064,接近临界失稳状态。

Stability analysis on the artificial island under wave loading

Oceanic foundation is threatened by the wave loading,which is the most frequently and austerity periodical dynamic load.Generally,Sea structures located on soft soil site is damaged by the foundation instability,not structure itself destroyed,because under the wave loading effect,the soil is disturbed and loading capability reduced,then foundation settlement increased largely and structure failed.Combined with artificial Island on beach-shallow sea,according to the existing research and the practice of study area and considering three characteristic water level(design high water level,design low water level and survival water level),different strength discount coefficients are selected considering the soften degree of wave loading to sea bed.Artificial Island model is build,and finite element method applied,then the paper analyzed the stability status,vertical and horizontal displacements under different water level and wave loading.The results indicate stability coefficients of artificial Island reduced apparently considering wave loading effects.Under the design low water level,when soil strength of sea bed is discount of 60% affected by wave,the stability coefficient falls to 1.064,which is close to critical instability.