干湿循环对压实红黏土动强度与动模量影响研究

Study on Effect of Dry and Wet Cycle on Dynamic Strength and Dynamic Modulus of Compacted Red Clay

采用自制一次成型模具制备压实度分别为90%、93%和96%的三轴试样,自制干湿循环试验装置对试样进行喷雾加湿和暖风干燥,定量模拟现场路基土含水率变化过程获得不同湿度和不同干湿循环次数的试样,通过常含水率动三轴试验测试其动强度与动模量变化规律。结果表明:累积应变随振次的变化分为塑性安定型、临界型和破坏型;临界动应力和最大动弹模随压实度的降低而减小,且减小幅度逐渐增大,随含水率的增大压实度的影响减弱;临界动应力和最大动弹模随含水率的增大而减小,临界动应力在含水率大于最优含水率时减小幅度相对较大;临界动应力和最大动弹模随循环次数的增多而降低,且降低幅度逐渐减小。

Triaxial samples with a compaction degree of 90%,93%and 96%were prepared using a self-made one-time molding mold,and the samples were subjected to spray humidification and warm air drying with a self-made dry and wet cycle test device.The samples with different humidity and different dry and wet cycles were obtained by quantitative simulation of the change process of subgrade soil moisture content on site.The change law of dynamic strength and dynamic modulus were tested by dynamic triaxial test of constant water content.The results show that the cumulative strain can be divided into plastic stability type,critical type and breaking type with the change of vibration times.The critical dynamic stress and maximum dynamic modulus decrease with the decrease of compaction degree,and the decreasing range increases gradually,and the influence of compaction degree weakens with the increase of water content.The critical dynamic stress and the maximum dynamic modulus decrease with the increase of water content,and the critical dynamic stress decreases relatively greatly when the water content is greater than the optimal water content.The critical dynamic stress and maximum dynamic modulus decrease with the increase of the number of cycles,and the decreasing range decreases gradually.