Effect Of Nano Graphite Powder On Mechanical And Permeation Properties Of Red Clay

With the sustainable development of the China-ASEAN Economic and Trade Area,the urban construction of the red clay regions,and the increasing of infrastructure construction,such as the high-speed railway and the expressway,there are higher and higher requirements for the engineering properties of the red clay.Foreign scholars use admixture like lime,cement,fiber to improve the engineering properties of the red clay,which has achieved some results.With the rise of nano materials,our country begin to widely use nano materials and nano technology in the field of the national defense technology,materials science and medicine etc.Thus a new type admixture of nano graphite powder was used to study the influence of the engineering properties of red clay.Nano graphite powder not only have unique small size effect and surface effect,but also have strong adsorption,high temperature resistance,and structural stability etc,so that it can adapt to the changes of external environment.In this paper,nano graphite powder is dispersed into red clay,according to the test procedure,we make some mixture of nano graphite powder and red clay?NGP-red clay?in different content and different dry density,through the triaxial consolidation undrained test,consolidation compression test and penetration test,to analyse the variation of the related engineering propertied of the mixture of NGP-red clay,and then we draw the following conclusions.?1?Under the same dry density 1.4 g·cm^-3,the shear strength and cohesion of NGP-red clay shows the law of increasing firstly while decreasing finally as the amount of admixture increase,but still greater than the red clay,and the optimum content is between 1%and 2%;the internal friction angle has no significant changes.Under different dry densities of 1.3g·cm^-3,1.4 g·cm^-3,1.5g·cm^-3,The shear strength of NGP-red clay is better with the increase of dry density,and the shear strength of red clay is the same as that of NGP-red clay.?2?The different amount of admixture of NGP-red clay belong to low compressive soil,the compressive coefficient of nano graphite powder and red clay decreases with the increase of the amount of admixture,which indicates that the nano graphite powder can effectively improve the void ratio of red clay.The compressibility of the same amount of admixture of nano graphite powder and red clay decreases with the increase of dry density,and the variation of compression coefficient of NGP-red clay and red clay is consistent with dry density change.The compressibility index of NGP-red clay is also opposite to its compressibility.?3?The permeability coefficient of NGP-red clay decreases with the increase of the amount of admixture,which further shows that the nano graphite powder changes the of void ratio red clay,and conclude that the nano graphite powder changed the microstructure of red clay.At last,combining with the SEM electron microscope scanning images,this paper give a summary of micromechanism that the compressibility,cohesion and permeability coefficient of nano graphite powder and red clay varies with the amount of admixture of nano graphite powder.