Experimental Study On The Relations Between Acoustic Velocity With Physical And Mechanical Properties Of Seabed Sediments Based On The Triaxial Test

The South China Sea is rich in resources, which is the most resource rich areas of the earth, and it has an extremely important strategic position for China concerned. The seabed sediments is an important object of Ocean Physics and Engineering Research. The related research and development and construction of the ocean urgently need to understand the physical and mechanical properties of seabed sediments.Introduce the research status at home and abroad of the acoustic characteristics and the physical and mechanical properties and the relationship between them of seabed sediments. Describe the principle and process of three axis test and velocity measurement of seabed sediments. Design a test program which study on the relationship between the sound speed and the physical mechanical properties of the seabed sediments. Measure the mechanical properties of seabed sediments by the triaxial test method in soil mechanics, and measure the velocity at the same time.It measures and analyzes the velocity data of seabed sediments in the triaxial test, and analyze the relationship between the acoustic velocity and the confining pressure of seabed sediments, it results that the acoustic velocity of seabed sediments and confining pressure in the test is positively related. Introduce the related physical properties of seafloor sediments, and analyze the relationship between the acoustic velocity and the moisture content, porosity, wet density and median particle size of seabed sediments, it results that the acoustic velocity and moisture content, porosity is positively related, and the acoustic velocity and the wet density, median grain size is negatively related.Study on mechanical properties of the South China Sea seafloor sediments, using triaxial test method of soil mechanics. Measure the failure stress of seabed sediments and draw the stress-strain curve and failure Mohr circle. The results obtained is the shear strength data.including the relationship curve between the stress value of failure point of seafloor sediments and the moisture content, wet density, median grain size and porosity. Through the analysis, it gets the conclusion that the stress value of failure point of seafloor sediments reaches the maximum value in moisture content between 40%-45% and porosity between 50%-55%. By comparison, it shows that the mechanical properties of seafloor sediment test sample are similar to the semi-brittle clay on land.It gets the conclusion that the acoustic velocity of the test samples of sediments with the damage stress, and friction angle are positively correlated, negatively correlated with cohesion. Calculate the elastic modulus and dynamic modulus of the seabed sediment samples in triaxial compression test, and then analyze the relationship between elastic modulus and dynamic modulus with the acoustic velocity and porosity of seabed sediments. A two-parameter empirical equation of sediment velocity is established, and the acoustic velocity of the sediment is drawn and the error of the velocity of sound is predicted.