荆门膨胀土的水稳定性及其力学效应

本文针对湖北襄荆高速公路膨胀土,在室内开展了原状土在脱湿吸湿过程的无侧限抗压强度演化特征与击实土的胀缩性状及力学效应试验研究,发现原状膨胀土的工程性状同时受含水率与裂隙性的耦合影响,耦合程度随裂隙发育程度和膨胀潜势等级而各异;膨胀土的CBR值随其含水率的变化规律类似于击实曲线,但CBR峰值含水率大于最佳含水率,并非压实度最大时CBR值也最大,CBR值取决于击实膨胀土浸水膨胀后的含水率与干密度以及结构所处状态;膨胀土路堤填筑除考虑压实度与CBR值要求外,尚需考虑胀缩总率的影响,为深入认识膨胀土的工程特性提供了帮助。

Water stability of Xiangjing expansive soils and their mechanical effect

The evolution characteristics of unconfined compression strength of intact sample at different stages of dehydration and the swelling-shrinkage behavior and its mechanical effect of compacted sample for expansive soils in Xiangjing Expressway, Hubei province are investigated in this paper. It is discovered that the engineering behavior of intact samples is controlled by the coupled action of water content and fissures, in which the coupled degree varies with the fissuring growth and swelling potential of the expansive soils, while the variation of California Bearing Ratio (CBR) of the expansive soils with water content is similar to the compaction curve. However, the water content of soil with the maximum CBR is higher than the optimum water content,therefore, the degree of compaction and CBR value can not reach the maximum at the same time, and the CBR value depends on the water content, dry density and structural state after soaking expansion of the compacted expansive soils. In the construction of expansive soil embankment, the influence of total swell-shrink ratio should be considered besides the degree of compaction and CBR value, and it is helpful to understand the engineering properties of expansive soils.