QUANTITATIVE ANALYSIS ON MICROSTRUCTURE OF CLAY SUBGRADE BY GROUTING

The method of clay subgrade by grouting has been widely used in construction with good economic benefits and value. Microstructure change is one aspect of reinforced effect for clay subgrade by grouting. Based on indoor tests, regularity of microstructure change in reinforcement and non-reinforcement clay subgrade is discussed and the amount of grouting and pressure with time curve are obtained. Firstly, the design of indoor grouting experiment is presented. Secondly, on the basis of scanning electron microscopy (SEM) and indoor test, the common physics and mechanical properties of the clay are determined. The main parameters on microstructure of the clay are found by studying the microstructure images before and after grouting. Finally, the change on microstructure parameters of clay are analyzed by a developed program. Mercury intrusion test is employed on the original and compound clay and variation of pore distribution and pore distribution range of pore size were obtained. It is found that the main pore radius of the clay is located between 0.05–1µm; the clay porosity; the total volume of pore; the total pore area and the pore radius are reduced in grouting compound. The experiment indicates that grouting reinforcement of clay subgrade has a marked effect.