Study On The Fractal Feature Of Soil Subjected To Freeze-thaw Cycles

Engineering practice and research shows that repeated heaving soil thaw settlement, and the resulting strength of the soil is the main cause weakening cold regions engineering structures of disease-prone, so research on the mechanism of freezing and thawing of the soil would reveal the freezing process, provide reasonable and effective prevention and control measures, and further enrich the frozen soil mechanics test system has a very important engineering significance. Taking the "Study on soil microscopic pore structure evolution and fractal dimension before and after freezing and thawing " which belong the Natural Science Foundation of Hebei Province as the basis, the study use scanning electron microscopy analysis of soil particle fractal dimension, and in-depth analysis of the freezing and thawing times magnification, water content, soil and other factors on soil characteristics influence of fractal dimension which is used as the media, to establish the relationship between the macroscopic and microscopic characteristics of soil mechanical properties. The main results are as follows:(1) In this paper, in order to make research more promotional by using two different soil plasticity index, and related physical properties of a test of physical indicators of soil were identified, including particle analysis, limit water content, and most moisture content, maximum dry density, freezing temperature.(2) On soil compaction into a different plasticity index sample, and after making 0 to 10 freeze-thaw cycles, using a scanning electron microscope, respectively, on the microstructure of the soil were observed on different soil freeze-thaw cycles particle and pore structure of the samples were observed. Study on the structural features of soil particle size distribution including microscopic pore diameter distribution, abundance and circularity of the particle, the porosity of the area and other relevant parameters change with the variation of the number of freeze-thaw cycles that occur.(3) For different soil samples after freeze-thaw cycles were studied mechanical properties of the samples after the unconfined compressive strength test to give the soil unconfined compressive strength, as measured by its engineering performance indicators. Study of freeze-thaw cycles of soil behind the stress-strain law through experiments and found that freezing and thawing of soil mechanical strength has a significant impact.(4) Through a combination of soil microstructure features and macro-mechanical nature, fractal theory, estimates the fractal dimension of soil particles, and use fractal dimension as a structural feature of soil microstructure metrics to establish a fractal dimension and thawing cycles, find the link between the fractal dimension unconfined compressive strength.