膨胀土胀缩性与裂隙性的湿干循环效应  

Effects of Cyclic Wetting and Drying on Swelling-shrinkage and Cracking of Compacted Expansive Soil

作　　者：周葆春 晏钰哲 陈翔宇 马全国 单丽霞 易先达 李颖 ZHOU Baochun;YAN Yuzhe;CHEN Xiangyu;MA Quanguo;SHAN Lixia;YI Xianda;LI Ying(Henan Unsaturated Soil and Special Soil Engineering Technology Research Center/College of Architecture and Civil Engineering,Xinyang Normal University,Xinyang 464000,China)

机构地区：[1]信阳师范大学河南省非饱和土与特殊土工程技术研究中心/建筑与土木工程学院,河南信阳464000

出　　处：《信阳师范学院学报（自然科学版）》2023年第4期647-655,共9页Journal of Xinyang Normal University(Natural Science Edition)

基　　金：国家自然科学基金项目(11772290,51009118);信阳师范学院青年骨干教师资助计划(2020GGJS-06)。

摘　　要：以压实度分别为100%、95%、90%、85%、80%的荆门黄褐色中膨胀土为研究对象,开展8次湿干循环试验,探索湿干循环过程中膨胀土的体积-裂隙-持水变化规律。结果表明:(1)历经3~7次湿干循环后,膨胀土的体积变化、含水率变化基本可逆。(2)随湿干循环次数增加,膨胀时程曲线、收缩曲线上移,表明湿干循环导致试样体积增大。膨胀稳定时间随湿干循环次数增加而减少,随制样压实度降低而减少。(3)试样脱湿完成后的裂隙面积随湿干循环次数增加而增大,5~6次湿干循环后,裂隙面积趋于稳定。历经足够多次湿干循环后压实中膨胀土裂隙率参考值为7%~10%。(4)每次脱湿完成后浸水,试样裂隙愈合;其中,前4次湿干循环,裂隙完全愈合。A series of tests for eight wetting-drying cycles were carried out on Jingmen yellow-brown expansive soil under five different initial compactnesses(100%,95%,90%,85%,80%,respectively).And the volume change-cracking-water retention behaviors during wetting-drying cycles were investigated.The conclusions were drawn as follows:(1)After three to seven wetting-drying cycles,the volume change and water content of the expansive soil were reversible.(2)With the increase of the number of wetting-drying cycles,the shrinkage curves and swelling curves moved up,which showed that the volume increase was induced by the wetting-drying cycles.Stability time for swelling decreased with the increase of the number of wetting-drying cycles,and with the decrease of initial density.(3)The crack area of the sample after drying increased with the increase of the number of wetting-drying cycles.And the crack area became steady after five to six wetting-drying cycles.After enough wetting-drying cycles,the reference value of surface crack ratio of compacted expansive soil was 7%~10%.(4)The cracks healed during wetting,and the cracks healed completely in the first four wetting-drying cycles.

关 键 词：膨胀土 胀缩性 裂隙性 湿干循环 收缩曲线 膨胀曲线 

分 类 号：TU443[建筑科学—岩土工程]