南阳膨胀土膨胀特性的试验研究

Experimental Study of Expansion Characteristics of Nanyang Expansive Soil

本文选取南水北调中线工程新乡段有代表性的膨胀土,采用固结仪对其膨胀变形特性进行了室内试验研究,探讨了上覆压力、起始干密度和含水率对膨胀土土体膨胀特性的影响。结果表明:不同含水率和压实度对土体膨胀率有显著影响,起始含水率越大土体膨胀率越小,压实度越大土体膨胀率越大;上覆压力对土体膨胀率有很大的抑制作用,随着上覆压力的增大,土体甚至产生负膨胀,因此在工程中可考虑施加一定的上覆压力来抑制膨胀土的膨胀。

The paper selects representative expansive soil of Xinxiang section of South-to-North Water Diversion Mid-line Project, adopts oedometer for indoor test study on expansion and deformation characteristics, and explores the influence of overburden pressure, starting dry density and moisture content on expansive soil expansion characteristics. The results show that different moisture contents and compaction degrees have prominent influence on expansion rate of the soil. The initial moisture content is greater, the soil expansion rate is smaller, the compaction degree is greater, the soil expansion rate is greater; overburden pressure has great inhibition effect on the soil expansion rate. The soil even generates negative expansion with increasing pressure of the overburden pressure, thereby we can consider to apply certain overburden pressure to suppress the expansion of the expansive soils in the project.