Experimental Research On Cementing Mechanism And Mechanical Properties Of Artificially Cemented Sand

Natural cementation can occur as a result of various geological processes that create bonds between soil grains.In sands,the cementing agents are often found to be silicates,amorphous silica,iron oxides,and calcium carbonate;One of the features of naturally cemented materials is that they have variable densities and degrees of cementation,and this is particularly the case for cemented sand.This variability and the difficulty of sampling without disturbing the cementation makes it difficult to study the fundamental behavior of naturally cemented materials.To avoid these difficulties,artificially cemented sand that the sand is added in cement cementitious material to formed artificial cemented sand have been used in many studies.The experimental research on the mechanical properties of artificially cemented sand can not only achieve good technical and economic effect for sand foundation treatment,but also has great theoretical and practical significance for the study of artificially cemented sand.In this article,cement clinker and standard sand were used to make artificial cemented sand samples,which were maintained in a constant temperature and humidity environment.The mechanical properties of artificially cemented sand were studied by unconfined compressive strength test and triaxial consolidation test.The stress-strain normalization problem were studied by analyzing the stress-strain curve of triaxial consolidation test.The microstructures of artificial cementation sand and the micro-morphology of cemented cementation were discussed by micro-experiment.The main research contents and achievements are as follows:(1)The unconfined compressive strength test of artificially cemented sand with different cement clinker incorporation ratio and different curing time was carried out.The variation law and failure form of cemented sand samples were analyzed,and the incorporation ratio of cement clinker(CV)and curing time(t)effect of cemented sand samples of the unconfined compressive strength formula,and the validity of the formula was verified by the experimental data of some researchers.(2)Triaxial consolidation test were carried out on the cemented sand samples with different cement clinker incorporation ratio and different confining pressures.The stress-strain curves and the strength indexes were analyzed to obtain the results ofdifferent cement clinker incorporation pressure strength index.(3)Under the condition of triaxial consolidation test,the Konder stress-strain hyperbolic model is used to study the stress-strain constitutive relation of artificial cementation sand by using the principal strain difference asymptotes as the normalization factor.(4)The mechanism of hydration and hardening of artificially cemented sand cement and the microcosmic experiment were studied.The changes of microscopic morphology under different cement mixing ratios and different curing times were analyzed.The mechanism of artificial cementation was obtained by combining the mechanical experiment rules.