考虑波浪与地震动力效应的曹妃甸海底斜坡稳定性探讨

STUDY ON SUBMARINE SLOPE STABILITY OF CAOFEIDIAN PORT CON-SIDERING WAVE AND SEISMIC DYNAMIC EFFECTS

波浪和地震等动力荷载容易引起斜坡海床失稳,进而引发海底滑坡,危及港口码头安全和海洋工程建设。本文以曹妃甸港南部深槽处海底斜坡为研究对象,考虑真实波浪荷载和地震荷载,采用有限元法和极限平衡法相结合的研究手段对海底斜坡的动态稳定性进行了定量化计算,探讨了动力效应对特殊环境下海底斜坡稳定性的影响机制。结果表明:(1)极端波浪荷载和地震动力荷载对海底斜坡稳定性影响很大,重现期为50a的波浪荷载和峰值加速度为0.15 g的地震动力荷载将引发海底斜坡失稳,且地震荷载将诱发海底斜坡产生较大位移;(2)动力效应会引发海床侵蚀和岩土体强度弱化,进而降低斜坡安全系数,这是稳定性分析中不可忽略的重要因素。

Dynamic loads such as waves and earthquakes can easily cause submarine slope instability,and further lead to the occurrence of submarine landslides,endangering the safety of ports,docks and marine engineering constructions.In this study,the submarine slope in the deep trough of south Caofeidian Port is investigated.To quantitatively calculate the stability of the submarine slope,the finite element method combined with the limit equilibrium method is used considering the effects of real wave loads and seismic loads.The mechanism of dynamic effects on the stability of submarine slopes under special circumstances is also investigated.The results show that extreme wave loads and seismic dynamic loads play an important role in the stability assessment of submarine slopes.Wave loads with a recurrence interval of 50 years and seismic dynamic loads with a peak acceleration of 0.15g can lead to the instability of submarine slopes.Seismic loads can produce larger permanent displacements on submarine slopes.In addition,the erosion and weakening of the rock and soil strength induced by dynamic effects can further reduce the safety factor of the slope under various working conditions,which cannot be ignored in stability analysis of submarine slopes.