关键词: 非饱和土, 土-水特征, 基质吸力, 超固结, 率敏性, 蠕变, 时效对应关系

Abstract: To study the long-term deformation after construction of high-filled soil under partial saturation, the rate sensitivity and creep tests of unsaturated compacted soil under controllable matric suction were carried out respectively, and the time-dependent corresponding relationship between them was analyzed. The rate-sensitivity tests used the triaxial shear method at different loading rates to analyze the effects of matric suction (0, 100, 200, and 300 kPa), loading rate (0.4 and 0.02 mm/min), and over-consolidation ratio (1, 4, and 8) on the strength and deformation characteristics of the soil. The 0.45, 0.65, and 0.85 times of shear strength are determined to be the third-order stress level loads of triaxial shear creep respectively. The triaxial shear creep tests of unsaturated compacted soil were carried out under four controllable matric suction forces (0, 100, 200, and 300 kPa), referring to the Chen loading method, and under three stress level graded loading. The results show that: 1) The rate sensitivity parameter ρ  of unsaturated compacted soil decreases with the increase of matrix suction, and its rate sensitivity also decreases. 2) With the increasing of matric suction, the initial maximum creep rate, stable creep rate and creep deformation of unsaturated compacted soil decrease significantly. 3) The strain rate-strain relationship line determined by the creep test is consistent with the strain rate-strain data points obtained by the rate sensitivity test, which proves that there is a certain time-dependent corresponding relationship between the rate sensitivity and creep, and this relationship becomes more significant with the increase of matrix suction. 

Key words: unsaturated soil, soil-water characteristics, matric suction, over-consolidation, rate sensitivity, creep, time-dependent correspondence