STUDY ON RELATIONSHIP BETWEEN PORE STRUCTURE PARAMETERS AND PERMEABILITY OF MALAN LOESS

A series of gas permeability and saturated penetration tests on Malan loess are accomplished by using the improved ZC-2015 air permeameter and TST-55 permeameter. We obtain two permeability parameters of gas permeability k_a and saturation permeability coefficient K_w respectively. The void ratio e is acquired by laboratory normal experiment. And the planar void ratio e₀ is obtained from electron microscopy(SEM)which is analyzed by image-pro plus(IPP). Then combining with the test results and using mathematical model, the relationship between macroscopic and microcosmic pore parameters and infiltration parameters are established. The results show that dry density of remolded soils increases, the number of particles per unit volume increases, porosity area decreases. The buried depth of undisturbed dry loess samples increases. Soil pore area and pore number, the average pore diameter of macropores and mesopores in loess significantly decrease. The semi-logarithmic linear model can eliminate the magnitude difference between K_w, k_a and the pore structure parameters, and the fitting results is better. lgK_w and lgk_a with e, e₀ show a good linear relationships. When the water content changes, the regulation of slope and intercept about the gas permeability fit lines change obviously. Due to uniform sample preparation, fitting curves of remolded soils show the high fitting degree. Comparing with the remolded loess, fitting degree of undisturbed loess in different depth is low because of structural difference of deposition process.