Research On Water Current Force Test Of Piled Wharf In Inland River

In recent years,with the increase of shipping density and the steady development of inland river transport industry after the filling of the Three Gorges Dam reservoir,the structure type of overhead vertical wharf has been widely applied in the construction of inland port.Currently,the calculation of water flow load in the design of ports mainly refer to " Code for Loads of Port Engineering M(JTS144-1-2010).This specification is suitable for calculation of the water flow load on the single pile and pile in row which are located in the middle and lower reaches of the Yangtze river and offshore with low flow velocity.Thus,it's necessary to research on the calculation method of water flow load for inland overhead vertical wharf with high flow velocity,which has a high structure and the form of a bent stress mainly.Based on the "Twelfth Five-Year" National Science and Technology Support Plan Project " Key Technology Research on Construction of Ports in Canalized Rivers of Mountain River",the prototype observation test was carried out in the site of the second stage of the Chongqing Guoyuan port project,and water flow load test on the first four common bent was carried out in detail.The main work and achievements of this program are as follows.(1)A set of water flow load field test system was developed,which consists of test strip(steel belt or pp board),cover plate,seal plate and a number of pressure sensors,waterproof wires,signal amplifier,signal acquisition instrument,computer,etc.Sensor system was composed of eight or four sensors installed within the test strips with an angle 45 °or 90 °.The test strips were made into round or square according to the component shape,respectively.(2)The arrangement and test method of the water flow load prototype observation test.Plane arrangement of the test point was made into T-shaped according to the principle of the load on the pile of first frame and the second column is given priority to,the rest of the pile is complementary principle;Vertical arrangement was emphasis on the second column piles of the firs bent,and the rest piles were secondary.Test sites with eight sensors are key test sites,only four are auxiliary.There are total eighteen test sites and ninety-two pressure sensors.Field test frequency is 100 HZ,and each test lasts 60 seconds.The whole test system need to be preheated at the beginning,and date was collected when the flow was relatively stable.(3)A set of water flow load test data processing method was put forward.To validate its reliability,the water flow load test data was conducted the fast Fourier transform and the frequency domain analysis?original data was transformed into the pressure value by the calibration formula?-Calculated the standard deviation of instantaneous pressure,boundary value was got by the average value plus or minus twice times value of standard deviation and the data outside the boundary was eliminated?Calculated flow pulsation pressure value?Fitted the distribution curve of water flow load along the pile ?The curve was conducted numerical integration to get the water load flow value by the application of MATLAB?Sum up the results and got the empirical formula of water flow load.(4)Distribution of water flow load on single pile.On the first shelving,the maximum to the minimum value of flow load is directly in front and behind of pile,respectively,and between the maximum and the minimum is a relatively smooth curve.However,on the latter two shelving,the maximum flow load and the minimum flow load are not in the right front of the flow direction,but somewhat offset,which appeared on the left and right sides of the pile.As a result,there is no longer a smooth curve,and bumps emerge in the middle of the curve.(5)Distribution of flow load on group pile.For parallel pile,when the velocity was small,the fluctuating pressure on the sensor decreased gradually as the angle between the piles and flow direction increased.Water flow load values of the pile along the transverse direction of the shelving first decreased and then increased from right to left.However,the water load values first increased and then decreased when the flow velocity was large.For series of pile,when the velocity was small,fluctuating pressure at the front of the pile decreases along the direction of the pile body.Sensor pressure first increased and then decreased around 30° positions and rear position.When the velocity is large,the fluctuating pressure has no apparent regularity.Water flow load was influenced by the block influence of series pile,flow load first decreased and then increased...