The Optimization Research Of The Tethers Of The Submerged Floating Tunnel

With the rapid growth of economy and the continuous progress of the society,the crossing of channels is becoming a more and more difficult problem to be solved.Up to now, various bridges above water and subsea pipelines have been designed successfully, however, it remains a tough problem to figure out a better way to cross those wide and deep straits like Qiongzhou strait. Submerged floating tunnel is an advanced approach to cross both lakes and straits. And it has attracted many countries’ attentions since it’s more economic, environmental, protecting, more convenient to install the electricity and water transporting pipelines to cross channels and straits, and have nothing to do with the eternal factors. Especially the prominent advantages of the tethered type of submerged floating tunnel has make it the center of research for experts at home and abroad. Currently, a great number of researchers have done a perfect job in the vertex-induced vibration of the tethers of the tethered submerged floating tunnel, but research on fatigue analysis of the tethers is inadequate.Thus, this paper shows a preliminary study of the various characteristics of the tethers of the tethered submerged floating tunnel under the effect of waves and current.Having reviewed a great number of references at home and abroad, firstly this paper gives a simple introduction of the concept of submerged floating tunnel and the research status, in the meantime analyzes the lectotype method of the newly proposed submerged floating tunnel, and takes the example of Qiongzhou strait, gives an appropriate type of submerged floating tunnel with the unique sea state there and the characteristics of different types of submerged floating tunnel, which is the tethered typed of submerged floating tunnel, subsequently establishes an flow field model by using Gambit, and leads the meshed model into Fluent to calculate, achieving an appropriate value of Cd, then taking the pairs of tethers, the inclination of tethers and the angles between tethers into consideration, establishes and calculates a number of models to do some mode analysis with the tethers of the tethered submerged floating tunnel, and the results indicate that when the current velocity is between 1.4m/s and2.4m/s, the first order mode vibration of the tethers of the submerged floating tunnel comes about, and that when the current velocity is between 2.7m/s and 4.0m/s, the second order mode vibration of the tethers of the submerged floating tunnel comes about.