Feasibility Study On Inorganic Chemical Mechanism Of Subgrade Soils

With the continuous development of highway construction, how to improve the embankment soil attracts more and more attention.During common soil curing technology,the soil inorganic curing agent has unique advantages,but still has limition,such as heavy workload on mixing ratio tests.The fundamental reason is that soil inorganic curing agent has not yet formed systematic and practical improvement theory and methods. Therefore, reaserch on mechanism of embankment soil inorganic improvement has great significance.This paper selects the common low liquid limit on north of Jiangsu province to research inorganic modified.In order to study the chemical mechanism, the paper combines the microscopic tests, thermodynamic calculation mechanism and macro-mechanical tests. The main work and achievements are as follows:(1)Analyzing sedimentary history and sedimentary environment of the region in Northern Jiangsu province, in order to analyze the reason of poor geotechnical properties of the low liquid limit in this area; Studying the basic physical fwith the results of interior foundation soil test; Reseaching on mineral chemical composition and specific surface microstructure by the method of XRD, BET Just preparing for the inorganic chemical stabilization.(2)Based on the chemical composition and the previous reseach, selecting curing agent which can react chemically with the chemical composition of the soil and can generate chemical potential cementing material. On the basis of solid surface chemistry, chemical thermodynamics, surface free energy chemistry theory, estimating the ratio of the curing agent and determining the test program.(3)Tracking the soil composition,the composition and the pH value of leaching solution in different curing time.Analyzing the chemical reaction rate, the reaction degree programs between the prime soil and the chemical modifier component added,in order to speculate the modification mechanism.(4)By micro and macro test,studying on the results of the inorganic modified of embankment soil and verifying the validity of the test program and the curing agent proportions which is in accordance with the basic principles of inorganic chemistry. Specific contents are as follows:A Analysis of particle size and gradation. Compare the particle size characteristics of the eleven samples.Analyzing the content of each granule, grading curve and maximum and minimum diameter of each test program, to prove the rationality of the agent selected.B Analysis of mineral composition. Analyzing mineral composition of samples qualitatively and quantitatively by the means of X-ray diffraction (XRD).Analyzing the relationship between the mineral composition and particle size of soil.C Analysis of the specific surface area.Testing the specific surface area and the pore size distribution by BET. According to changes in surface area t, analyzing the relationship between changes in the specific surface area and mineral composition.D California Bearing Ratio (CBR) test. Simulating the worst case by soaking the soil under water and analyzing the stability in water.Analyzing the relationship between the mineral composition, particle size distribution, specific surface area and the CBR value of soil.This paper applies the chemical fundamentals such as the principle of minimum energy inorganic chemistry, Gibbs free energy principle and solid surface chemistry to the subgrade inorganic chemical modification technology.By micro and macro experiment, verifying the rationality of Test program, verifying the easibility of applying basic principles of inorganic chemical reactions to the improvement of embankment soil.