Abstract: Minimum void ratio is an effective physical index to determine the compactness and pore characteristics of soil mass. A fast and effective method to determine the minimum void ratio of soil mass can provide reliable parameters for soil consolidation and stability. Most of the model parameters corresponded to the ratio of fine-coarse particle size one by one, so it is difficult to estimate the minimum void ratio of fine-coarse mixed materials. By analyzing the grain size composition, deposition and consolidation stability of tailings, and combining with the minimum void ratio test results of tailings with 8 different grain sizes and 7−9 different fine grain contents, a power function of the minimum void ratio distribution model parameters of tailings with different grain size fractions was obtained. Based on the grain size fraction of mixed tailings, the exponent values to determine the power function relationship of parameters were given. Six groups of other soil materials grain size within the range of grain size fraction and three groups grain size without the range of grain size fraction were used to verify the model parameters. The results show that the model considering the influence of grain size fraction has simple parameters and high accuracy in estimating the minimum void ratio of different soil materials. The minimum void ratio given is reasonable, and it can provide a reliable calculation method for estimating the minimum void ratio in the field of geotechnical engineering.

Key words: minimum void ratio, grain size fraction, fines content, grain size