Investigation On Response Of Pore Pressure Around Pile Foundation To Random Wave And Current

With the promotion of strategy in the transportation and marine engineering,China has constructed a mass of traffic junctions and sea-crossing bridges,as important connections between regions,has made great progress in the construction.However,the complicated marine environment has brought uncertainties in the construction’s utilization safety.Especially for the pile foundation located on the seabed,the steady of soil around them would influence overall and service life directly.Thus,it is essential to investigate pore-water pressure response of seabed around bridge pile foundations under random wave-current.In this paper,numerical and experiment models are adopted together to analyze the pore pressure response of seabed soil around bridge pile foundations affected by random wave and current systematically.Firstly,a numerical model named as interactive model of random wave and current,pile foundations and seabed is proposed,and its reliability is verified by a flume experiment of random wave and current.Based on the Open FOAM platform,a random wave current model is established by Ola Flow solver,and a porous-elastic seabed model is established by solving the Biot(QS model)equation.The one-way coupling mechanism of the random wave current model and the seabed model is further combined.Then,the random wave flow flume test is carried out.The accuracy and reliability of the new numerical model are verified by the test results and theoretical spectrum,which proved that the numerical model in this paper can better simulate the pore pressure response around the pile under the action of random wave flow.Secondly,the response of pore water pressure of soil around single pile under random wave current is investigated based on the numerical model of random wave current pile foundation seabed interaction,combined with random wave current flume experiment.It is found that the distribution of pore water pressure around a single pile decreases along the depth direction of the coastal bed,increases first and then decreases along the propagation direction of random wave current,and decreases along the circumferential direction of the pile.Then,the parameter analysis of the response of soil pore pressure around a single pile is carried out by changing the characteristics of random wave and current.The results show that the amplitude of pore pressure around a single pile increases with the increase of wave height and period.Finally,the random wave and current-pile-seabed interaction numerical model is used to research the response of pore water pressure around two piles under three-dimensional random wave and current.It is indicated that the maximal pore-pressure caused by three-dimensional random wave and current is less than that caused by two-dimensional random wave and current;The propagation direction of three-dimensional random wave and current has a certain influence on the distribution of pore-pressure around the two piles.In addition,the maximal pore-pressure around the two piles is analyzed by changing the distance between the two piles,and the “equivalent liquefaction depth coefficient” is proposed,which has a great useful guideline for the construction of sea-crossing bridges.