粘性土在不同温度下龟裂的发展及其机理讨论

Development and Mechanism of Desiccation Cracking of Clayey Soil under Different Temperatures

通过试验,研究了粘性土在不同温度下龟裂的发生和发展规律,运用计算机图像处理和编程技术,对不同温度下获得的粘性土龟裂网络的几何结构和形态特征进行了定量分析。结果表明:龟裂的发展过程可分为四个阶段,温度效应十分明显。温度越高,龟裂形貌越简单,龟裂条纹越宽,而在较低的温度下,龟裂的形貌比较复杂,龟裂条纹纤细且间距较密,表面比较破碎;从粘土矿物双电层理论对龟裂的形成机理提出了一种新的解释;在试验中还发现了一个十分有趣的现象,即大部分龟裂都呈垂直或近似垂直相交,被龟裂分割出的区块形状多以四边形为主,其它多边形较少;最后提出了龟裂研究的下一步课题。

An experimental project was undertaken to investigate the effect of temperature on initiation and propagation of desiccation cracks of clayey soil, and the computer image processing techniques and programming were applied to quantify the geometric structure and morphologic characteristics of surface crack networks after drying under different temperatures. The results show that the soil cracking generally experiences four stages of development which is significantly influenced by temperature. With increasing temperature, the crack patterns of soil samples tend to be simpler, and the crack width increases; Under lower temperature condition, the crack pattern is more complicated, the crack width is finer and the soil surface is more fractured; A new interpretation on the cracking mechanism is proposed based on double-layer theory of clay; An interesting phenomenon was discovered in the testing that most of the cracks intersect almost perpendicularly, and most of the polygons separated by cracks are quadrangular. The future research work on desiccation cracking is proposed.