Study On The Influence Of Load Form On The Fluidization Process Of Liquefiable Cargo

The safe transportation of liquefiable cargo is an important topic in the research on modern transportation safety of watercraft.When the water content of the cargo exceeds a certain value in the process of transporting the bulk cargo,the phenomenon of water precipitation will occur under the action of wind and waves and other external loads,and the surface will form a muddy mixture.Under the continuous action of external load,the mud mixture formed on the surface will continue to move freely,and the slurry liquid will move to the sides of the ship.And the liquid flow is not easy to return to the initial position.This will continue to increase the ship side tilt,resulting in the ship's center of gravity instability.In bad weather,ships can capsize and casualties are huge.Fluidization accidents occur suddenly and are difficult to rescue.The fluid cargo belongs to soil in essence.Firstly,according to the soil mechanics knowledge,the basic properties and other mechanical indexes of soil are studied,and the mechanism and influencing factors of liquefaction of soil under external load are discussed.Then,the definition and influencing factors of "fluidization" of fluidable goods in IMSBC rules are studied,and compared with the vibration liquefaction theory in soil mechanics,the rationality of using the vibration liquefaction mechanism of soil in soil mechanics to explain the fluidization mechanism is demonstrated theoretically.By carrying out dynamic triaxial consolidation test and fluidization test of iron concentrate on swing table,the macroscopic fluidization performance of iron concentrate under different frequency and different amplitude and the variation rule of pore water pressure under saturated condition are analyzed.The fluidization process was analyzed under different external loads under the condition of 10% moisture content.The general rule of fluidization of iron concentrate under external load is explained experimentally.It is found that pore water pressure increases with the increase of burial depth.From the macroscopic situation of swing table test,it is found that a critical value of frequency(6-7Hz)in the range of 2Hz-10 Hz makes fluidization occur slowly.The fluidization process can be divided into initial drainage stage,partial shunt stage and full fluidization stage.Finally,FLAC3 D software was used to simulate the fluidization of saturated iron concentrate under various frequency amplitudes,so as to analyze the variation rules of overstatic pore water pressure and overstatic pore water pressure ratio.The general rule of iron concentrate under external load is explained by numerical simulation.The numerical calculation shows that at various frequencies,the overstatic pore water pressure is different.The overstatic pore water pressure value increases with the increase of burial depth,and there is a critical value(6-7Hz)between 2-10 Hz,which makes the pressure value change from fluidizable to partial splitter.