不同干密度条件下植被土干缩开裂特性试验研究

Desiccation cracking behavior of vegetated soil with various dry densities

植物护坡的干缩开裂现象十分常见。为了探究植被土的干缩开裂特性,开展了一系列室内干燥试验,设置了4种不同干密度(1.3,1.4,1.5,1.6 g/cm^(3))的植被土试验组和裸土对照组试样,定时测量试样质量并监测其表面裂隙发育过程,采用自主研发的CIAS系统,对土体裂隙进行定量分析。试验结果表明:①随着干密度的增大,植被土蒸散速率逐渐降低。②在相同干密度的条件下,植被土的失水速率比裸土慢,并且产生裂隙时的临界含水率小于裸土产生裂隙时的临界含水率。③植被土的裂隙发育过程与干密度密切相关,随着干密度的增加,裂隙网络形态形成时对应的含水率越高。④与裸土相比,在相同干密度条件下,植被可以降低土体表面裂隙率和裂隙平均宽度,增加土体裂隙密度。

Desiccation cracking in vegetated slopes is a common phenomenon.In order to investigate the desiccation cracking characteristics of a vegetated soil,a series of desiccation tests are carried out in this study.The vegetated and bare soil groups with four different dry densities(1.3,1.4,1.5,1.6 g/cm^(3))are selected.The weight of each soil sample is regularly measured,and the development of surface cracks is monitored.A self-developed system CIAS is adopted to quantitatively analyze the surface crack pattern during the drying process.The experimental results show that:(1)The evapotranspiration rate of the vegetation soil decreases with the increase in the dry density.(2)Compared with the bare soil,the vegetated soil sample has a slower water loss rate and a smaller critical water content under a certain dry density.(3)The dry density has a significant influence on the desiccation cracking behavior of vegetated soils.The larger the dry density,the larger the water content corresponding to the formation of the crack network pattern.(4)With a given dry density,the vegetated soil has a smaller surface crack ratio and an average crack width,but a larger crack density compared with the bare soil.