冻融循环条件下延迟时间对水泥改良低液限粉土动力特性影响试验研究

Experimental Research on the Effect of the Delay Time under Freezing-Thawing Cycle to the Dynamic Characteristics of the Improved Cemented Low Liquid Limit Silt

模拟路基真实的冻融循环过程,设计冻融试验,制作冻融试验箱,进行改良土试样的冻融循环试验。通过动三轴试验,研究在冻融条件下,延迟时间对水泥改良低液限粉土的动强度、动弹性模量、动变形以及超孔隙水压力的影响。结果表明:在相同的冻融次数下,动强度和破坏循环次数随着延迟时间的增加而降低;在相同的冻融次数及一定动荷载幅值作用下,屈服应变则随着延迟时间的增加而增加;延迟时间短的试样,动弹性模量值较大,但随应变的衰减较平缓,且趋于一个稳定值;不同延迟时间试样达到相同应变幅值时所增长的孔压值不同,延迟时间越长,孔压越大;当轴向应变幅值大于10-3后,产生累积孔隙水压力。

For analoging the practical process of freezing-thawing cycle to subgrade, the freezing and thawing cycle test for soil-cement was proceeded by designing the scheme of freezing and thawing cycle test and then making the proof box for freezing and thawing cycle. Through the dynamic triaxial tests on the cemented low liquid limit silt subject to freezing and thawing cycles, effects of the delay time on the dynamic strength, the dynamic elastic modulus, the dynamic deformation, and the excess pore water pressure of the mentioned silt were studied. Results show that the dynamic strength and the failure cycle times will be decreased with the increase of the delay time under the identical freezing and thawing numbers. Under the identical times of freezing-thawing and the given dynamic load, the yield strain will be increased with the increasing of delay time. The shorter delay time is, the larger dynamic elastic modulus will be and degenerating gently with the strain, and vice versa and dynamic modulus of different work conditions will be degenerating to steady-state value eventually. The increasing pore water pressure reaching identical strain will be varying from the delay time. The longer delay time is, the larger pore water pressure will be. Moreover, when the axial strain is more than 10^-3, the accumulated pore water pressure will be created remarkably.