花岗岩崩岗红土层土体胀缩特性研究

为研究崩岗土体因水分变化而发生干湿胀缩的特性,采集福建省安溪县典型崩岗区的红土层土样,通过室内无荷膨胀试验和收缩试验,分析不同初始干密度(1.3,1.4,1.5 g/cm^3)、不同初始含水量(15%,20%,25%和30%)下土体的无荷膨胀率和线缩率。结果表明:当含水量较低时,初始干密度越大土体膨胀率也越大;当初始干密度相同时,土壤膨胀率随其初始含水率的增大而减小。当初始含水率相同时,土样膨胀率随其初始干密度的增大而增大。不同处理的土样收缩过程有一定差异,初始含水率高的土样线缩率大,土壤膨胀和收缩过程不一致,且均为不可逆过程。该研究结果在一定程度上揭示了土壤含水率和干密度与崩岗侵蚀之间的关系。

Study on the Expansion and Contraction Characteristics of Red Soil Layer in Benggang of Granite Area

To study the characteristics of Benggang soil expansing and contracting with the moisture changes, soil samples of the red soil layer in the typical Benggang area of Anxi County, Fujian Province were collected. Through the experiment of non-charge expansion and shrinkage, non-charge expansion rates and the linear shrinkage rates of the soil samples under different initial dry densities (1.3, 1.4 and 1.5 g/cm³) and different initial soil water contents (15%, 20%, 25% and 30%) were analyzed. The results showed that the soil expansion rate was larger when the initial dry density increased in the low soil moisture. When the initial dry density was the same, the soil expansion rates decreased with the increases of initial water contents. When the initial soil moisture content was the same, the soil sample expansion rates increased as its initial dry density increased. There was a difference in the shrinkage process of soil samples with different treatments. The soil shrinkage rate with high initial water content was large, and the soil expansion and contraction processes were inconsistent and both processes were irreversible. The result revealed the relationships between soil water contents and dry densities and Benggang erosion.