不同湿化状态下压实红黏土的压缩特征  

Compression Characteristics of Compacted Red Clay under Different Wetting States

作　　者：谈云志[1] 吴翩[1] 郑爱[1] 万智[2] 

机构地区：[1]三峡大学三峡库区地质灾害教育部重点实验室,湖北宜昌443002 [2]湖南省交通科学研究院,湖南长沙410015

出　　处：《实验力学》2013年第6期709-715,共7页Journal of Experimental Mechanics

基　　金：国家自然科学基金项目(51009084);湖南省交通科技进步与创新计划项目(No.200910;No.201045)

摘　　要：为模拟路基土体在不同湿度状态下的压缩特征,以湖南长沙-韶山-娄底高速公路的红黏土路基填料为研究对象,开展吸水自由膨胀、吸水限制膨胀和不浸水等三种湿化状态下的压缩实验研究。本文根据实际应力与固结屈服应力的关系提出确定土体压缩系数的改进方法,并与目前规范中推荐的压缩系数(a1-2)进行了比较,验证了改进方法更加合理。然后,对比分析不同湿化状态下的压缩指标。结果表明:吸湿后的土体压缩性均大于不浸水土的压缩性;但浸水吸湿限制膨胀和浸水吸湿自由膨胀后再压缩,前者的压缩性要大于后者的压缩性。最后,从孔隙结构的细观角度探讨了固结应力对土体孔隙结构的作用模式,发现固结作用主要影响孔径d>10μm范围内的孔隙分布。In order to simulate the compression behavior of subgrade soil under different wetting conditions,taking red clay subgrade packings collected from Changsha-Shaoshan-Loudi highway as subject investigated, compression experiments were carried out under three wetting states including soaking swelling freely, soaking swelling restricted and no soaking, respectively. An improved method to determine soil compression coefficient is put forward in this paper, based on relationship between the actual stress and the consolidation yield stress. Result from the improved method was compared with compression coefficient （al-2） recommended by current specification, which confirms the more rationality of the improved method. Comparison results among compression indexes under different wetting states show that the compressibility of moisture absorption samples is larger than that of no soaking ones. But the compressibility of samples soaking swelling freely is smaller than that of samples swelling restricted ones. At last, the effect of consolidation stress on soil pore structure was discussed from the perspective of meso-pore structure, which found that the consolidation affects only pore distribution of apeture d〉lOμm.

关 键 词：红黏土 固结屈服应力 吸力丧失 压缩变形 湿化效应 

分 类 号：TU443[建筑科学—岩土工程]