摘要
裂隙性是膨胀土的典型工程地质特性之一,对其工程性质有重要影响,直接或间接地导致各种工程问题。通过对重塑膨胀土开展室内干湿循环试验,对获得的裂隙数字图像采用图像处理技术进行一系列预处理操作,提出了表面裂隙率、裂隙条数、裂隙总长度、裂隙平均宽度和绝对收缩率等量化指标,定量描述裂隙的形态特征,分析干湿循环过程中压实膨胀土的裂隙发育规律。结果表明:含水率和干湿循环次数是影响膨胀土裂隙发育的重要因素。随着含水率的减小,重塑膨胀土的裂隙发育程度总体上有增加的趋势。表面裂隙率、裂隙条数和总长度随含水率的减小逐渐增加,绝对收缩率随含水率减小而增大,而裂隙宽度与含水率之间没有明显的规律;随干湿循环次数的增加,裂隙进一步发育,裂隙条数、裂隙总长度、表面裂隙率增加,绝对收缩率总体增大,但裂隙平均宽度存在减小的现象,这与后期发育的大量微裂隙有关。
Desiccation cracking is one of the typical engineering geological characteristics of expansive soil and has a major impact on engineering properties of expansive soils. It can lead to many engineering geological problems directly or indirectly. After indoor wetting-drying circle tests on remolded expansive soil, obtained crack digital images are disposed by a series of pre-processing operations with the image processing technique. A series of parameters are propose to describe the morphological structure of the desiccation crack pattern quantitatively. It includes the crack ratio of surface, crack number, total crack length, average crack width and absolute shrinkage ratio. And the impact of wetting-drying circles on characteristics of expansive soil crack development are analyzed. The results show that wetting-drying cycles and moisture content are some significant factors affecting the development of expansive soil desiccation cracks. With decreasing moisture content, there is an increasing trend of the development of remolded expansive soil cracks overall. The surface crack ratio, number of cracks and total length increase with decreasing moisture content and absolute shrinkage ratio grows greater, but there is no obvious regularity between average crack width and water content. Desiccation cracks develop further with increasing wetting-drying circles and the numbers of cracks, total crack length and surface crack ratio increase, and absolute shrinkage ratio increases in the mass. Nevertheless, there is a reduced phenomenon on average crack width, which is related to the development of micro-cracks later.
出处
《工程地质学报》
CSCD
北大核心
2016年第5期856-862,共7页
Journal of Engineering Geology
基金
优秀青年科学基金项目(41322019)
国家自然学科基金项目(41572246)
国家自然科学基金重点项目(41230636)
中央高校基本科研业务费专项资金
"青蓝工程"资助
关键词
膨胀土
干湿循环裂隙
数字图像处理
定量分析
Expansive soil, Wetting-drying cycle, Desiccation crack digital image processing, Quantitative analysis
