冻融循环对不同比例风化砂改良膨胀土膨胀力的影响

目的]研究风化砂改良膨胀土的膨胀力与风化砂掺量、冻融循环次数之间的定性和定量关系,为风化砂改良膨胀土用作公路路基提供理论依据。方法]在膨胀土中分别掺入0,10%,20%,30%,40%,50%的风化砂,在分别经过0,1,3,6,9,12次冻融循环后,在固结仪上进行膨胀力测试。结果]风化砂的掺入可明显降低膨胀土的膨胀力;在相同的冻融循环次数下,风化砂改良膨胀土的膨胀力随掺砂比例的增大而减小,膨胀力降低的幅值随掺砂比例的增加亦逐渐减小;在相同的掺砂比例下,风化砂改良膨胀土的膨胀力随冻融循环次数的增大而减小,膨胀力降低的幅值亦逐渐减小。当掺砂比例相同时,风化砂改良膨胀土的膨胀力与冻融循环次数的自然对数呈线性负相关关系。结论]不同的冻融循环次数和不同的掺砂比例对膨胀土的膨胀力均有影响。

Influences of Freezing-thawing Cycle on Expansive Force of Expansive Soil Improved by Different Proportional Weathered Sand

Objective] The qualitative and quantitative relations between the expansive force of weathered-sand-improved expansive soil and the effects of weathered sand content, the number of freezing-thawing cycles on the expansive force were studied. Methods] Weathered sand was put into the expansive soil with the proportions of 0,10%,20%,30%,40%,50% and the expansive force was tested on the consolidation test apparatus in condition of freezing-thawing cycles with the times of 0,1,3,6,9,12. Results] The expansive force of weathered-sand-improved expansive soil reduced obviously. Both the expansive force of weathered-sand-improved expansive soil and the extent of the expansive force reduces as the proportion of weathered sand increased in the same time of freezing-thawing cycles. In contrast, the two items reduced as the times of freezing-thawing cycles increased in the same proportion of mixed weathered sand. The expansive force of the weathered-sand-improved expansive soil and the natural logarithm of the number of freezing-thawing cycles showed negative linear correlation relationship in the same content of weathered sand. Conclusion] Both of the freeze-thaw cycles and the proportion of mixed sands all affect the expansive force of expansive soil.