Analysis Of The Effects Of Different Nanomaterials On The Properties Of Remolded Red Clay In Guilin

Red clay is a kind of special clay formed by the interaction of physical weathering,chemical weathering and laterization of carbonate rocks in the climate of alternating heat and moisture.It is mainly distributed in the eastern Sichuan,Yunnan-Guizhou plateau,Hunan ? Hubei and Guangxi ? Guangdong region of China.Guilin region of Guangxi is one of the most commonly developed carbonate karst areas in China.Red clay has good mechanical properties of high strength and low compressibility,it corresponds to the high porosity ratio,high plasticity,high natural moisture content and other special engineering properties,causing foundation uneven settlement and deformation of structures,slope instability,pavement cracking and other diseases,with the vigorous development of the national infrastructure construction,more and more is also high to the requirement of the engineering properties of red clay.Therefore,three nanomaterials including nano-graphite powder,nano-bentonite and nano-calcium carbonate were used as admixtures in this paper to discuss the influence of nano-materials on the engineering properties of red clay.Due to the characteristics of small particle size,high surface energy,large specific surface area and large proportion of surface atoms,nanomaterials have nano effects such as surface effect,macroscopic quantum tunneling effect,quantum size effect and small size effect.Each kind of nano material but also has its unique properties,under the conditions of red clay is the optimum moisture content,respectively to three kinds of nanometer materials mixed with 1% of the content,making different dry density test of soil samples,and Compared with red clay without nano materials,comparing the red clay by liquid plastic limit test,triaxial shear test and direct shear test,X-ray diffraction test,X-ray fluorescence spectrum,electron microscope scanning,mercury injection test to the following conclusion:(1)Macroscopically,different nano-materials changed the liquid plastic limit,shear strength index and shear strength of remolded red clay.Nano-graphite powder had the most obvious effect on improving the mechanical properties of remolded red clay,followed by nano-bentonite and nano-calcium carbonate,which weakened the mechanical properties of remolded red clay.With the increase of confining pressure and dry density,the mechanical properties of the remolded red clay increased step by step.(2)In terms of material composition,the red clay minerals and oxides before and after the addition of nanomaterials were qualitatively and quantitatively analyzed by X-ray diffraction test and X-ray fluorescence spectrum,and the principle of mechanical changes of remolded red clay caused by changes in major elements and mineral composition was analyzed by changes in their properties and contents.(3)In microcosm,through the electron microscope scanning test,mercury injection test analysis to reshape the red clay before and after adding nanometer materials,the change rule of microstructure on the microscopic mechanism of the change of the macro mechanical properties,the results showed that the red clay soil particles mainly grain group,laminated structures,structural framework,the form of nanometer materials to reshape the small pore is opposite bigger,the influence of red clay nano graphite powder,nano bentonite make its porosity decreased significantly,can significantly improve structure reshape the red clay.