Study On Microstructure And Constitutive Model Of Organic Disseminated Sand Mortar

To study the optimum mixture ratio of the organic matter impregnation sand micro structure and the constitutive model of cement-soil,starting with organic impregnation sand as the research object,through gas chromatography mass spectrometer for the organic matter contents of organic matter impregnation sand qualitative and quantitative analysis,through the EDS and XDR test on the chemical composition analysis.And then to the optimal mixture ratio of organic contaminated soil as the research object,the organic matter were analyzed by using different instars of electron microscope scanning,impregnation sand soil microstructure along with the change of age and the consolidation mechanism;Through unconfined compressive strength test to study the failure mechanism and the compressive strength,and through the least value method and the stress-strain curves obtained under the action of the uniaxial constitutive model;Last by not consolidated undrained triaxial shear test to study the stiffness changes and the revised-Zhang Bengou Duncan model.The main research results of this paper is as follows:(1)It is concluded that organic impregnation sand in the 19 kinds of molecular formula and molecular structure of the organic matter of molecular structure contains a large number of carboxyl,after various reactions generate H+,make organic impregnation sand show weak acid condition,main composition is SiO2 organic impregnation sand;(2)Through the ages of 7,14,21 and 28 days of organic impregnation sand soil microstructure analysis found that increasing particle volume and pore size decreases,and between particles by rough gradually smooth surface;(3)Through the MATLB quantitative analysis is made on the result of the electron microscope scanning 7,21 and 28 days corresponding grain percentage of 0.6550,0.8158 and 0.8458;(4)Under the optimal mixing proportion of organic impregnation sand consolidation mechanism including hydration hydrolysis reaction of impregnated cement and organic matter,carbonate,hard condensation reaction and humic acid,humic acid hindered the hydration reaction of soil at the same time;(5)Uniaxial compression state soil damage including against external forces,instability and failure of elastic deformation,crack spreading and four stages;(6)Triaxial test of concrete results are as follows:(1)Sample damage including vertical penetration,symmetric cone type cracks,single cone type,single diagonal crack,oblique cracks and oriel six types;(2)Under the optimal mixing proportion of organic impregnation sand soil characterized by obvious sclerosis type,reaches maximum stress and strain of 5%to 6%,the brittle failure sample happen at any time,when the strain between 6%and 7%can be clearly observed that the crack in the sample;(3)The maximum stress value of cement soil specimen of the same age with confining pressure was positively than relationship,confining pressure and the peak stress and corresponding strain inverse proportion,water,soil stiffness hardening speed and ages were positively than relations;(7)On the basis of single shaft under the action of stress strain curve,using the least square method under the action of the uniaxial constitutive model of segmented elastic-plastic constitutive research;(8)Based on the stress-strain relationship under different confining pressure,the Mohr-coulomb’s law and the related theoretical study is suitable for the optimal mixture ratio organic impregnation sand soil under the revised Duncan-chang model parameters.