Experimental Investigation On The Cable Tension Of Tunnel Element Under Mooring Condition

During the construction of immersed tube tunnel, the behavior of cable tension and the motion of tunnel element under mooring condition will directly influence the accuracy and safety in the process of immersion.Therefore, the paper carried out the physical model test of tunnel element under mooring condition, and achieved quite good results, realized the aim of optimizing the mooring scheme of tunnel element.This paper studied the mooring force of tunnel element with floating barge under wave-current action, and investigated the effects of the pontoon, wave height,wave period, current velocity,cable angle,cable length,etc.on the mooring force, through a series of wave-current tests, conclusions are as follows:a. The mooring force of mooring system with pontoon is greater than that without pontoon,for this reason,it is better to choose the mooring system without pontoon.b. The direction of wave and current only influnences a little of the mooring force if the direction changes in a certain range.c. The mooring force turns greater as the wave period bigger,but it no longer grows when the wave period reach a certain number.lt is related to the natural period and damping of the mooring system.d. The mooring force turns greater as the wave height bigger,generally it holds a linear relationship. And under single wave action,the mooring force is maximum when the angle of the mooring line is 0°;while with current action,it is 45°e. The mooring force turns greater as the current velocity bigger,and the mooring force reaches maximum when the angle of the mooring line is 45°.f. When the angle of the mooring line is less than 30°, the wave is the controlling influence factor; When the anle of the mooring line is between 30℃nd 45°, the current is the controlling influence factor.g. The linear relationship of the mooring force changes with wave and current under single wave or current action is better than that under both wave and current action.This is due to the mutual influence between wave and current.h. The mooring force under both wave and current action is not the simple combination under single wave and sigle current actions,there may be a superposition or counteraction relationship.i. The mooring force of mooring schemeⅡ(4 mooring lines) is greater than that of mooring schemeⅠ(6 mooring lines),but not so much.j. For mooring schemeⅡ,the mooring force for 200m(the length of the mooring line) is greater than that of 350m,the ratio is about 25%.It manifests the mooring force turns greater as the mooring line shorter.k. The length of the mooring line can be properly shorten and the angle of the mooring line should be within 30°...