An Experimental Study of Irregular Wave Forces on Multiple Quasi-ellipse Caissons

  • 格式:pdf
  • 大小:1021.47 KB
  • 文档页数:9

J.Marine Sci.App1.(2014)13:265—273 DoI:l0.1007/sl1804—014.1256—8 

An Experimental Study of Irregular Wave Forces on Multiple Quasi——ellipse Caissons 

Xiaozhong Ren ,Peng Zhang2,Yuxiang Ma3 and Yufan Mengl 

』.Dalian Jiucheng Municipal Design Co.Ltd.,Dalian 11600 ̄China 2.CCCC Water Transportation Consultants Co.Ltd.,Beijing IO000Z China 3.StateKeyLab.ofCoastalandOffshoreEng.,Dalian UniversityofTechnology,Dalian 11602 ̄China 

Abstract:An experimental investigation of irregular wave forces on quasi.elliF,se caisson structures is presented.Irregular waves were generated based on the Jonswap spectrum with two significant wave heights,and the spectrum peak periods range from 1.19 s to 1.8l s.Incident wave directions relative to the cenffe line of the multiple caissons are from 0。to 22.5。.The spacing between caissons ranges from 2 to 3 times that of the width of the caisson. The effects of these parameters on the wave forces of both the perforated and non。perforated caissons were compared and analyzed.It was found that the perforated caisson can reduce wave forces,especially in the transverse direction.Furthermore,the relative interval and incident wave direction have significant effects on the wave forces in the case ofmultiple caissons. Keywords:relative wave length;relative interval;incident wave direction;relative wave he J ght;quasi—ellipse caisson;perforated quasi—ellipse caisson;irregular wave forces 

Article ID:1671--9433(2014)03・-0265--09 1 Introduction Gravity dolphin structures are widely used in harbour construction(Zhao,2008;Hou,2008).This kind of structure has many advantages including being able to support large loads.has strong structural integrity and durabiliⅣ.and has good resistance to freezing and earthquakes.Furthermore,it is relatively quick to construct and easy to ensure building quality as it involves minimum underwater works. The quasi—ellipse caisson is a new type of gravity dolphin structure.It was first adopted for the construction of the gravity dolphin wharf of the Dalian ore terminal(phase II project)(Bai and Hu,2006).A caisson is normally made up of three parts,the front and rear parts are the semicircle sections and the middle part is fl rectangular section. Compared with the conventional circular caisson,the quasi.ellipse caisson is considered better suited for the large—scale precast concrete construction because a wharf structure with a single row of quasi.ellipse caissons are less Received date:2013-12.O9. Accepted date:2Ol4—05—12. Foundation item:Supported by the National Natural Science Foundation of China under Grant No.51l09032.and the National Natura1 Science Foundation ofChinaunderGrantNo.50921001. Corresponding author Email:renxiaozhong2000f l63.com ◎Harbin Engineering University and Springer-Verlag Berlin Heidelberg 2014 likely to suffer from uneven settlement in comparison with the use of two rows of circular caissons fZhu and Ding, 2007;Dong,2008).In a similar way as the perforated circular caisson(Neelamani et a1.,2000;Viiayalakshmi et a1.,2007)and the perforated rectangular caisson(Li et a1., 2002,2003。2005;Chen et a1.,2003;Suh el a1.,2006;Liu et a1.,2006,2007,2008)that have long been investigated and used in practice,it is expected that the perforated quasi.ellipse caissons will also reduce the reflected waves in front of the caisson and the wave forces on the caisson. At present,despite their Successfu1 use in practice the hydrodynamic behaviour of the quasi—ellipse caisson is little known,especially in regards to the perforated quasi—ellipse caisson.The linear wave force on a quasi.ellipse caisson has recently been calculated using a two—dimensional source representation method by Ren et a1.(2009).Wang et a1. (20l1、have also successfully developed a 3D domain numerical mode1.But these calculations are limited to a single quasi—ellipse caisson without considering the multiple quasi—ellipse caissons and perforated quasi-ellipse caissons. The wave forces on the multiple quasi.eUipse caissons are expected to be very different from the wave forces on a single caisson as the adjacent caissons may interact strongly with each other in a complicated way.In order to get a better understanding of the characteristies of multiple quasi.ellipse caissons and provide necessary guidance tor engineering design,the wave forces on the multiple quasi.ellipse caissons were studied in a scaled physieal mode1.Both non・-perforated and perforated quasi..ellipse caisson arrays were tested for a range of wave and caisson parameters.The relationships between the wave forces and wave parameters such as relative wave length,incident wave direction,and relative wave height are presented and discussed.