不同压实度荆门弱膨胀土的一维膨胀-压缩特性

One-dimensional swelling-compression characteristics of Jingmen weak expansive soil under different compactnesses

为探讨压实膨胀土的体变行为,以荆门弱膨胀土为研究对象,借助高压固结仪对6种制样压实度下的膨胀土试样进行了一维无荷载膨胀和含一次卸载-再加载循环的压缩试验。基于膨胀试验结果,构建了膨胀时程方程,通过参数分析,明确了方程参数的物理意义,并建议了膨胀时程曲线3阶段的划分方法。基于压缩试验结果,探讨了固结屈服应力、压缩指数Cc、回弹指数Cs、膨胀力与制样压实度、土体结构性、膨胀势、孔隙比的相关关系。试验结果及其分析表明,膨胀土体积变化是膨胀势与外部荷载、湿度变化的耦合作用结果,且具有强烈的水-力路径依赖性。

In order to investigate the volume change behaviour of compacted expansive soil, the one-dimensional swelling- compression tests are carried out for Jingmen weak expansive soil associated with six different compactnesses. Based on the results of one-dimensional nonloaded swelling tests, a time-swelling formula is presented which can fit the tested time-swelling curve satisfactorily with the physically meaningful parameters. Furthermore, the time-swelling curve can be characterized as three segments divided by a method presented. On the other hand, the results of the one-dimensional compression tests are used to investigate the interactive relationship between consolidation yield stress, compression index Ce, swelling index Cs, swell pressure and sample compactness, soil structure, swelling potential, void ratio in detail. The test results show that the volume change of compacted expansive soil is the consequence of the effects coupled moisture, external load, and swelling potential. And the volume change depends heavily on the hydro-mechanical path.