膨胀土大面积浸水现场试验  

Large-scale filed immersion tests for expansive soil

作　　者：王亮亮[1] 杨果林[1] 秦朝辉[1] 

机构地区：[1]中南大学土木工程学院,长沙410075

出　　处：《工程勘察》2013年第3期37-41,45,共6页Geotechnical Investigation & Surveying

基　　金：铁道部科技研究开发计划课题(2010G106-B)

摘　　要：为研究原位膨胀土在大面积浸水条件下的变形特征,在典型膨胀土地段做了面积为5.1×15m2的浸水试验,试验历时17d。试验结果为:(1)膨胀变形过程可分为4个阶段,初始快速线性膨胀阶段、过渡阶段、缓慢线性膨胀阶段、稳定阶段;(2)膨胀速率基本呈现"短时极大→小→稳定"的规律,其中浸水0～1.5h是膨胀速率最大的时期,最大膨胀速率达13.26mm/h,之后膨胀速率迅速降低,平均膨胀速率只有0.09～0.78mm/d;(3)膨胀土的渗透模式受土体中微裂纹数量、土颗粒间收缩膜强度以及膨胀单元受力情况影响;通过分析,建议将连续3d膨胀变形量不大于0.02mm,总浸水时间不少于两周作为膨胀土现场大面积浸水的稳定标准。In order to study the deformation characteristics of the field expansive soils under the large area immersion conditions, the large-scale field immersion tests with the water pool of 5.1 × 15.0m^2 are carried out, and the tests are sustained for 17 days. The testing results are as follows： （1） The swelling process could be divide into four phases according to the swelling curves, the initial rapid swelling phase, the gradual transition phase, the slowly increasing and gentle swelling phase; （2） The rate of swelling settlement varies with the immersion time in such patterns： maximal, low and gentle, during 0 -1.5h immersion time, the maximal swelling rate appears, and the maximal value is 13.26mm/h, then the swelling rate reduces rapidly and goes into low rate term, the mean value is 0.09 -0.78mm/d; （3） The infiltration process is affected by the quantity of the tiny cracks, the water film strength between the soil particles and the stress conditions of swelling unit. The steady criterion for the large area filed immersion tests of expensive soil is proposed, that is the rate of the swelling deformation is less than 0. 02 mm/3d, and the immersion time is larger than 2 weeks.

关 键 词：膨胀土 大型现场浸水试验 膨胀变形特征 高速铁路 

分 类 号：TU413[建筑科学—岩土工程]