Experimental investigation on motion responses of immersing tunnel element under wave actions

Experiment was carried out to investigate the motion responses of the tunnel element in the immersion under wave actions and the tensions acting on the controlling cables of its immersing system.The variation of motion responses of the tunnel element and cable tensions against relative wave height H/h,relative width b/λ and relative immersing depth d/h were obtained.Results show that motions of the tunnel element have strong nonlinearity when the immersing depth is relatively small.The motion responses decrease rapidly with the increase of b/λ and d/h.The wave height has effects on the non-dimensional displacements of the tunnel element and the effects are obvious in the case of small immersing depth.The maximum tension of the offshore side cable is slightly higher than that of the onshore side cable.The phase difference of the cable tensions is obvious in the case of small immersing depth.The cable tensions increase with the decrease of b/λ,and decrease as the wave height decreases and the immersing depth increases.