Analysis Of Microstructure And Mechanical Properties Of Marine Soil In Bohai

With the continuous development and utilization of marine resources,more and more large-scale projects are spreading to the seabed.Due to the unique underwater environment,it has been proven that the physical and mechanical properties of marine soil are very complex.Based on existing rich scientific research and extensive engineering practices,the microstructure of marine soil particles and pores,such as their shape,distribution,and connection methods,closely affects their engineering properties.Therefore,increasing research on the physical and mechanical properties and microstructure of marine soil is necessary for future engineering practice and has necessary guiding significance for the implementation of engineering.On the basis of summarizing the current status of macroscopic and microscopic research on marine soil,this article aims to study the influence of the structure of marine soil on its macroscopic mechanical properties from a microscopic perspective,and further deepen the understanding of the engineering characteristics of marine soil.A combination of macroscopic and microscopic experiments was used to conduct liquid-plastic limit,direct shear,consolidation,X-ray diffraction,and SEM electron microscopy scanning tests on the marine soil between Ant Island and Pig Island in the Bohai Sea,Using methods such as IPP and SPSS software to study the evolution of macroscopic mechanical and microscopic characteristics of marine soil.A combination of qualitative and quantitative methods was used to study the relationship between microstructure characteristics such as shape coefficient,particle shape fractal dimension,pore shape fractal dimension,particle distribution fractal dimension,and pore distribution fractal dimension with shear strength parameters,compression index,and consolidation coefficient.Provide relevant references for subsequent research on Bohai marine soil.The research shows that in the Direct shear test,the shear strength,internal friction angle and cohesion of marine soil increase linearly with the increase of the water content set in the test.In the consolidation test,as the consolidation pressure increases,the void ratio and consolidation coefficient first slowly decrease,then rapidly decrease,and finally approach a fixed value.The compression index increases to a certain value and then slowly decreases.Through quantitative analysis of electron microscopy scanning images,it was found that in the consolidation test,the number of pores decreases with the increase of consolidation pressure.The pore ratio,particle and pore distribution fractal dimension decrease,while the shape coefficient,particle and pore shape fractal dimension increase,indicating significant anisotropy in the soil.In Direct shear test,with the increase of shear strength,the shape fractal dimension of particles and pores,and the distribution fractal dimension of pores increase,while the distribution fractal dimension of particles decreases.Through multiple stepwise regression analysis and grey theory analysis,correlation analysis was conducted between various macroscopic mechanical characteristic indicators and microscopic parameters.The values of compression index,consolidation coefficient,internal friction angle,cohesion,etc.were closely related to the microscopic parameters of soil,and showed different correlations.