秦鹏举, 刘宇菠, 闫庆晨, 等. 2023. 高温干燥-室温加湿循环作用下压实黄土体变和电阻率特征[J]. 工程地质学报, 31(2): 358-367. doi: 10.13544/j.cnki.jeg.2021-0781.
    引用本文: 秦鹏举, 刘宇菠, 闫庆晨, 等. 2023. 高温干燥-室温加湿循环作用下压实黄土体变和电阻率特征[J]. 工程地质学报, 31(2): 358-367. doi: 10.13544/j.cnki.jeg.2021-0781.
    Qin Pengju, Liu Yubo, Yan Qingchen, et al. 2023. Effect of cycles of drying at high temperature and wetting at ambient temperature on volume change and electrical resistivity behaviors of compacted loess[J]. Journal of Engineering Geology, 31(2): 358-367. doi: 10.13544/j.cnki.jeg.2021-0781.
    Citation: Qin Pengju, Liu Yubo, Yan Qingchen, et al. 2023. Effect of cycles of drying at high temperature and wetting at ambient temperature on volume change and electrical resistivity behaviors of compacted loess[J]. Journal of Engineering Geology, 31(2): 358-367. doi: 10.13544/j.cnki.jeg.2021-0781.

    高温干燥-室温加湿循环作用下压实黄土体变和电阻率特征

    EFFECT OF CYCLES OF DRYING AT HIGH TEMPERATURE AND WETTING AT AMBIENT TEMPERATURE ON VOLUME CHANGE AND ELECTRICAL RESISTIVITY BEHAVIORS OF COMPACTED LOESS

    • 摘要: 工程地质环境中,高温加速土体干燥,降雨浸湿土体。干湿循环导致土体劣化易引起基础设施和建筑物损害。所以,有必要研究干湿循环对压实黄土体变特性的影响以评价地基和路基等的稳定性。本研究制备了初始含水量为11%,不同干密度(1.5 g·cm-3、1.6 g·cm-3和1.7 g·cm-3)的3组试样。试样在80 ℃下干燥,然后室温下浸入去离子水中饱和,直达预定的干湿循环次数。同时,用数字LCR仪测量土样电阻率,以表征土样的结构变化。采集干燥状态试样表面图像,以分析裂隙开展情况。干湿循环结束后,进行饱和土样的恒应变速率(CRS)试验,获取压缩曲线并确定压实黄土的变形参数。结果表明,随着干湿循环次数的增加,土样电阻率逐渐增大,并且裂隙比增大。无竖向压力下,开始从非饱和状态高温干燥引起土样收缩,随后室温饱和使土样膨胀;之后,从饱和状态高温干燥引起土样膨胀,随后室温下饱和土样引起其收缩。另外,随干湿循环次数增加,弹性压缩指数增加,对于较低密度土样塑性压缩指数减小而屈服应力增大,对于较高密度土样塑性压缩指数呈现增大趋势而屈服应力减小。本研究可为工程实践中压实黄土工后沉降分析提供理论基础。

       

      Abstract: In the environment of engineering geology,high temperatures accelerate drying of the soil mass that is also subject to wetting by rainfall. Dry-wet cycles tends to cause degradation of the soil mass,which can seriously damage the infrastructure and buildings on the soil mass. Investigation of dry-wet cycling on deformation behavior of compacted loess is indispensable to evaluate the stability of basement and subgrade in the engineering practice. In the present work,we fabricated three groups of samples with one water content of 11% and three different dry densities(1.5,1.6 and 1.7 g·cm-3). The samples were desiccated at 80 ℃,followed by wetting at an ambient temperature through immersing the samples into deionized water until a designated dry-wet cycling number. Upon cycling,electrical resistivity was measured by a digital LCR meter to characterize the structure change of the samples. Besides,the photographs of the sample surface after desiccation were taken to observe crack evolution. At the end of the cycles,constant rate of strain(CRS)was imposed on the saturated samples to determine the deformation parameters of the compacted loss. Results shows that the electrical resistivity increases due to the increase of crack ratio as the cycling numbers increase. Since the vertical stress is zero,the volume of the unsaturated compacted samples decrease as undergoing initial drying in high temperature,followed by expansion as the samples are immersed into water. Subsequently,expansion continues in the process of desiccating the samples at 80 ℃ and shrinkage then occurs after saturating the samples. Besides,as dry-wet cycling numbers increases,the elastic compressibility index increases,and the plastic compressibility index decreases and the yield pressure increases for samples with low density but the tendency is opposite for samples with high density. This study can provide a theoretical basis for post-construction settlement analysis in the engineering practice.

       

    /

    返回文章
    返回