Study On The Microstructure Characteristics Of Bio-silicon And Its Effect On The Physical And Mechanical Properties Of Deep-sea Clay

With the rapid development of marine engineering,and gradually advancing from the offshore to the deep ocean,marine geological disasters such as submarine earthquakes,submarine landslides,and debris flows have also seriously affected the reliability and safety of marine engineering.Researchers have found that biosilicon is abundant in lake sediments and marine sediments.When the mass content of biosilicon in the sediment exceeds 10%,it will have a significant impact on the physical and mechanical properties of the sediment.Biosilicon is an abbreviation of siliceous microbial debris,and it is an amorphous silica.The main types are diatoms,radiolarians,and sponge bone needles.From the genesis of bio-silicon,it can be seen that it widely exists in areas with high biological productivity.A complete biosilica wreck shell,which has a cavity inside and is rich in tiny holes on the surface,belongs to a porous fossil material.The effect of biosilicon on the water holding characteristics of marine sediments determines the physical properties of marine sediments and further determines the natural state of the foundation soil of marine structures;the impact of biosilicon on the compression characteristics of marine sediments largely determines The stability of submarine slopes and seabed foundation soils further affects the reliability of marine structures;the effect of biosilicon on the shear characteristics of marine sediments determines the bearing capacity of marine structure foundation soils and further affects marine structures Security.Therefore,it is of great significance to study and deeply understand the effects and laws of marine silicon on water holding characteristics,compression characteristics,and shear characteristics.At present,most researches on biosilica include qualitative analysis of microstructure and macroscopic properties,and lack of quantitative analysis and comparison of the two.This paper combines the characteristics of deep-seabed soils in the western South China Sea basin,and uses artificial mixed ratios of diatomite and kaolin to analyze the microstructure,water retention characteristics,consolidation compression characteristics,and triaxial shear characteristics of biosilicon.First,the scanning electron microscope was used to observe the microstructure characteristics of biosilicon in the South China Sea soil and diatomite.At the same time,the content of biosilicon in the South China Sea soil and diatomite was accurately determined by the optimized alkaline extraction method.Secondly,by studying the influence and law of the content of biological silicon on the water holding characteristics of the mixed soil,the main reasons for the high water content,high liquid-plastic limit and high porosity of the mixed soil caused by the increase in the content of biological silicon are the main reasons Water.Based on the results of scanning electron microscopy and particle size analysis,a quantitative water content geometric model of biosilica was established.The excess water content calculated by the test was compared with the calculated excess water content of the model,and the accuracy of the quantitative water content geometric model was verified.And proposed the calculation method of the true moisture content of bio-silica.It laid a foundation for further considering the influence of the microstructure and content of biosilicon on the mechanical properties of marine soil.Next,the influence and laws of biosilicon on the consolidation and compression characteristics of mixed soil were studied.Consolidation compression experiments of mixed soils with different biosilicon content were carried out.The influence of biosilicon on the compressibility index of mixed soil was explored.The unified inherent consolidation compression line model line is compared,and the inherent consolidation compression line model for biosilica containing modification is established,and the inherent consolidation compression lines with different biosilicon content are normalized to obtain better results..It provides a theoretical basis for further studies on the consolidation and compression characteristics of marine silicon containing biosilicon,and the stability analysis of seafloor slopes.Finally,the effects and laws of biosilicon on the shear strength characteristics of mixed soils were studied,and a static triaxial test for consolidation and undrainage of mixed soils with different biosilicon contents was carried out.The reason for the increase of the shear strength of the soil under the static load of the soil with the increase of the internal bio-silicon content.It further explained that biosilicon can promote the stability of the submarine slope under static load.The completion of the above work has great reference and guiding significance for the research on the physical and mechanical properties of marine soils containing biosilicon in the field of marine rock and soil or marine geology.However,for complex geotechnical engineering issues,whether the quantified geometric model of biosilicon containing water and the modified intrinsic consolidation compression line model established in this paper are effective,further research and further understanding are needed.In addition,this article also did research on the seabed sediments in the offshore area.For the columnar samples of seabed sediments collected from two proposed wind power sites in Yangjiang and Huizhou offshore of Guangdong in 2018,the granularity and basic physics were performed indoors.Parameters,liquid-plasticity indicators,and full-flow penetration strength tests have explored various physical and mechanical properties of surface sediments in the seabed off the coast of Guangdong,and are related to the sediments in the offshore waters of Guangdong and the shallow foundation of the proposed offshore wind power project.The foundation geotechnical design provides important data.