棕丝加筋红黏土的裂隙特性研究

Study on crack characteristics of palm fiber reinforced red clay

在干旱气候环境中,红黏土具有显著的裂隙性,由此引发大量的工程地质灾害。为抑制红黏土裂隙的发展,通过在红黏土中添加棕丝改良并开展室内干缩开裂实验,研究棕丝长度及掺量对红黏土裂隙发展及特征指标的影响。结果表明,在干燥开裂过程中,红黏土的裂隙特征指标均经历了从快速增长到趋于稳定的阶段,但变化规律并不完全相同,当裂隙率趋于稳定时,裂隙长度逐渐增加而裂隙宽度却呈现减少趋势。土表中央裂隙产生早于边界裂隙,中央裂隙间交叉角度约90°,边界裂隙与边界大体平行。随着棕丝掺量的增大,改良土的裂隙率和裂隙宽度相应减小,裂隙长度先减小后增大;随着棕丝长度的增大,改良土的裂隙率、裂隙宽度均先减小后增大,裂隙长度先减小后增大最后减小。采用0.3%的棕丝掺量、10mm的棕丝长度,并在适当的含水率状态下可有效抑制红黏土裂隙的发展。

In arid climates, red clay has significant fissures, which leads to a large number of engineering geological disasters. In order to inhibit the development of red clay fissures, the influence of palm fiber length and dosage on the development and characteristic indicators of red clay fissures is studied by adding palm fiber to red clay and carrying out indoor dry shrinkage cracking experiments. The results show that in the process of dry cracking, the fracture characteristics of red clay experience a stage from rapid growth to stabilization, but the variation laws are not exactly the same. When the fracture rate tends to be stable, the fracture length gradually increases, while the fracture width shows a gradual decrease trend. The soil surface central fissures occur earlier than the boundary fissure, the intersection angles between the central fissures are about 90°, and the boundary fissures are roughly parallel to the boundary. With the increase of palm fiber dosage, the fracture rate and fracture width of the reinforced soil decrease accordingly, and the fracture length decreases first and then increases. With the increase of the length of the palm fiber, the fracture rate and fracture width of the reinforced soil reduce first and then increase, and the fracture length reduces first and then increases and finally decreases. Palm fiber dosage 0.3%, palm fiber length 10mm and appropriate moisture content can effectively inhibit the development of red clay fissures.