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中国最大的内陆咸水湖———青海湖日渐“消瘦”,记者日前从青海省气象科学研究所了解到,近25年来,青海湖湖面已萎缩近150平方公里。经卫星遥感测量,青海湖西岸和北岸陆地相对推进距离分别达到1566.3米和3266.9米,年平均推进距离分别为62.6米和130.6米。青海省气象科学研究所专家表示,青海湖在1975年~2000年的25年间,湖岸总体变化趋势是陆地相对向湖水方向推进,湖岸形体整体萎缩。除此之外,水位下降、沙化、旱化、草原退化等已使青海湖百“病”缠身。如不采取有效的保护措施,长此下去,青海湖不是变成沙湖就会变成死湖。美丽的青海湖百“病… 相似文献
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随机波浪作用下座床式大直径薄壁圆筒防波堤的动力分析空间模型 总被引:1,自引:0,他引:1
随机波浪作用下座床式大直径薄壁圆筒防波堤的动力运动过程分为:摇摆、摇摆—小滑移运动和摇摆—大滑移运动三种运动模态,引入了控制侧向滑移的阻滑板—弹簧—阻尼器运动模型,建立了相应的动力分析空间模型。在大型有限元软件ANSYS中利用参数化设计语言APDL进行二次开发实现其空间模型,并把此空间模型计算结果与文献[1]中建立的平面模型计算结果比较,获得了一些有价值的结论,表明了本模型和方法对随机波浪荷载作用下大直径薄壁圆筒防波堤动力响应的数值模拟的可行性和有效性。 相似文献
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The large cylinder is a new-type structure that has been applied to harbor and offshore engineering. An analytic method of the relationship between loads and the structure displacement is developed based on the failure mode of deep embedded large cylinder structures. It can be used to calculate directly the soil resistance and the ultirnate bearing capacity of the structure under usage. A new criterion of the large cylinder structure, which discriminates the deep embedded cylinder from the shallow embedded cylinder, is defined. Model tests prove that the proposed method is feasible for the analysis of deep embedded large cylinder structures. 相似文献
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An optimization mathematical model of the pile forces for piled breasting dolphins in the open sea under various loading conditions is presented. The optimum layout with the well distributed pile forces and the least number of piles is achieved by the multiplier penalty function method. Several engineering cases have been calculated and compared with the result of the conventional design method. It is shown that the number of piles can be reduced at least by 10%—20% and the piles‘ bearing state is improved greatly. 相似文献
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