摘要
膨胀土的变形特性包括裂隙性和胀缩性,其中开裂和收缩特性对于膨胀土边坡变形研究具有重要的作用。取陕西汉中十天高速公路边坡膨胀土进行室内干湿循环试验,研究不同干湿循环次数下脱湿过程中膨胀土的开裂、收缩特性,观察脱湿完全后裂隙的扩展特性,探讨收缩的方向性随干湿循环次数和初始含水率的变化规律。结果表明:前2次干湿循环脱湿过程中,裂隙与收缩开展剧烈;脱湿过程中裂隙面积率先增大后减小,第1次干湿循环的裂隙面积率峰值最小,且出现时间较早;脱湿过程中收缩面积率先增大,后趋于平缓,随着干湿循环次数的增加,收缩面积率逐渐增大直至第三次干湿循环趋于稳定,前2次干湿循环其差值最大;随着干湿循环次数的增加,试样的变形量逐渐增大,收缩比开裂更早趋于稳定;裂隙的宽度和长度近似正态分布,裂隙面积概率随着裂隙面积增加逐渐减小;膨胀土的收缩具有明显的各向异性性质,初始含水率越高,各向异性表现越明显。
The deformation characteristics of expansive soil include crack and swell-shrink, the cracking and shrinking characteristics for the research of the deformation in expansive soil slope play an important role. Taking expansive soil of slope in ten days highway in Hanzhong city in shanxi province to do the test of wetting-drying cycles indoor, studying cracking and shrinking properties of expansive soil in the dehumidifying process under different wetting-drying cycles, observing the extensional features of crack after dehumidifying completely, to explore the direction of the shrinkage varying with wetting-drying cy- cles and the initial moisture content. The results showed that：in 2 times of dehumidifying process under wetting-drying cycles, crack and shrinkage develop acute. The area ratio of crack increases in dehumidif- ying process firstly, then decreases, it is minimum and appears earlier in the first wetting-drying cycle. The area ratio of shrinkage increases firstly in dehumidifying process, then tends to stable, the area ratio of shrinkage increases gradually with the increase of wetting-drying cycles, it doesn＇ t tend to be stable until the third wetting-drying cycle, and the change is the biggest in 1 - 2 wetting-drying cycles. With the increasing of wetting-drying cycles, the deformation of specimen gradually increases, shrinkage earlier than crack tends to be stable. The width and length of crack appear to be normal distribution, the proba- bility of the cracking area with the increasing of the cracking area decreases. The shrinkage of expansive soil has obvious anisotropy, the higher the initial moisture content is, the more apparent anisotropy becomes,
出处
《西安科技大学学报》
CAS
北大核心
2016年第4期541-547,共7页
Journal of Xi’an University of Science and Technology
基金
陕南地区高速公路膨胀土边坡预防性养护技术研究项目(14-13k)
国家自然科学基金(41172262)
教育部新世纪人才支持计划项目(No.NCET-12-1044)
陕西省重点科技创新团队计划(No.2014KCT-30)
关键词
膨胀土
干湿循环
裂隙
收缩
面积率
各向异性
expansive soil
wetting-drying cycles
crack
shrinkage
the area ratio
anisotropy
