Support-Span of Tube Piers for Seabed Vacuum Tube:A Theoretical and Simulation Study

Mechanical properties of Seabed Vacuum Tube (SVT) supported by piers, an advanced transportation across straits and bays, were mathematically formulated with static/dynamic models, theoretically analyzed in material mechanics and numerically simulated to estimate the support-span. The influence of the realistic situation, including but not limited to the dimensions/natural-frequency/weight/mechanical-behavior of tube, depth/floatingload/current of sea-water, and load/speed of trains, on support-span was investigated. The steel tube, 2 ~ 3. 4 m in diameter and 10 ~ 30 mm in thickness, was exemplified in the calculation. The analyzed and simulated results show that the reasonable support-span should be longer than 100, 500 m at most. If necessary, tension legs between piers significantly increase the support-span. Moreover, we found that the support-span depends strongly on pier's resistances against the pressure/extraction-force/transversal-force, but weakly on the tube mechanical strength.