Experiment And Quantitative Research On Variation Regularities Of Microstructure Of Clayey Soils Under Loads

The complex characteristic, such as noncontinuity, nonuniformity, anisotropy and uncertainty, which clayey soils show in macroscopic scale in engineering, are fundamentally dependent on noncontinuity and uncertainty of soil microstructure. Based on the former research and lots of microstructure quantification experiments, we want to learn variation character of soil microstructure, study change regularities of structural parameters under continuous loads and combine them with macro physical and mechanical behavior of clayey soils, thus we can explain and grasp the engineering characteristic from soil microstructure. The main research contents are as follows:1. After finishing reading a large number of domestic and international relevant documents, the main characteristics of microstructure quantification research in our country and in the world have been compared with and summarized. The main characteristics of experiment system made by our lab and test methods are also evaluated.2. The hardware of the existing test system of soil microstructure is upgraded and the means of observation is improved and adjusted to adapt to the characteristics of soil samples such as high water content, external roughness and complicated shape of microstructure unit.3. Some relevant digital image-processing methods are introduced in quantitative research on microstructure in order to optimize the quality of pictures, preparing for obtaining quantificational parameters effectively next.4. On the basis of rationality and easy operation, we divide microstructure morphology of clayey soils, define main structural parameters and determine algorithms.5. Through two parallel experiments, i.e. carrying out test observation respectively on clayey soils which contain a little swelling clay and certain soils with high compression coefficient by using microstructure test system, we analyse photos obtained to acquire quantitative information of microstructure under continuous loads.6. Change regularities of microstructure in compressive procedure are studied, and the inner relationship among quantitative information, structural parameters and macro physical and mechanical behavior is also analysed.7. Structural analyses of these two kind of clayey soils mentioned above are carried out to determine quantitative relationship between engineering geology parameters and structural factors of them and tentatively probe the controlling mechanism of microstructure and characteristics of soil mechanics.