为研究石灰改良膨胀土的水稳定性,以某边坡弱膨胀土及石灰改良膨胀土为研究对象,进行了击实试验、无侧限抗压强度试验和压缩模量试验,并引用其他学者的相关土水特征曲线(SWCC)试验结果,分析了石灰改良膨胀土的水稳定特性。结果显示石灰改良膨胀土的可击实范围比素土宽,且最优含水率和最大干密度随掺灰率的增大分别线性增大和线性减小;石灰改良膨胀土经过1 d的吸湿后,无侧限抗压强度与压缩模量降低幅度最大,之后随着吸湿天数的增加,无侧限抗压强度和压缩模量降低的幅度逐渐减小,最终趋于稳定;经过1次干湿循环后,无侧限抗压强度降低幅度最大,之后随着干湿循环次数的增加,无侧限抗压强度降低幅度逐渐减小。试验后的石灰改良膨胀土强度及模量的衰减程度较素土有了较大幅度的降低,表明石灰改良土的水稳定性有了较大的改善。此外,SWCC的研究表明石灰改良膨胀土的水稳定性得到了较大幅度的提高。

The water stability of lime-treated expansive soil is researched through compaction test, unconfined compression test and compression modulus test on weak expansive soil and lime-treated expansive soil in association with the test results of soil-water characteristic curve (SWCC) by other scholars. Results reveal that the compaction scope of lime-treated expansive soil is wider than that of natural expansive soil, and the optimum water content and the maximum dry density respectively increases and decreases linearly with the increment of lime content. The reduction of unconfined compressive strength and compression modulus of lime-treated expansive soil is the largest after one-day water absorption, and with the increase of water absorption time, the reduction rate gradually gets smaller and finally tends to be stable. Moreover, the reduction of unconfined compressive strength is up to maximum after 1 day’s wetting-drying cycle, and with the increasing of wetting-drying cycle, the reduction rate also decreases. The decreased margins of unconfined compressive strength and compression modulus of lime-treated expansive soil are remarkably smaller than that of natural expansive soil, indicating that the water stability of lime-treated expansive soil is greatly improved. In addition, researches of SWCC also show that the water stability of lime-treated expansive soil is improved.