干湿循环与荷载耦合作用下红黏土胀缩特性-《建筑科学与工程学报》

文章信息/Info

Title:: Swelling-shrinking Characteristics of Red Clay Under Coupling Effect of Dry-wet Cycles and Loading

Author(s):: CHEN Kai-sheng, LI Zhen; College of Civil Engineering, Guizhou University

Keywords:: dry-wet cycle; loading; red clay; swelling-shrinking characteristic; coupling effect

摘要:: 为获取符合工程设计的实际参数，对常规固结仪进行了改造，提出了一种模拟土体在荷载作用下的干湿循环试验方法，对红黏土进行了有荷载条件模拟干湿循环过程的试验研究，得到其胀缩变形的变化规律。结果表明：该方法可以实现不拆卸试样干湿循环试验，克服了以前荷载为0的土体干湿循环试验的缺陷，为工程设计提供更加合理的技术指标；干湿循环下红黏土的胀缩变形不可完全恢复，上覆荷载可以抑制其膨胀性，增强其收缩性；荷载小于50 kPa时，试样膨胀，且压实度越大和初始含水率越小，膨胀性越强；荷载大于100 kPa时，试样收缩，压实度越小和初始含水率越大，收缩性越强；第1次干湿循环对红黏土胀缩性能影响最为显著，随着干湿循环次数的增加，胀缩率曲线越来越平缓，胀缩性能趋于稳定状态。

Abstract:: In order to obtain the actual parameters conforming to the engineering design, the conventional consolidation apparatus was reconstructed. A new dry-wet cycle test method of simulating soil under load was invented. The dry-wet cycle experimental research of red clay was carried out under load conditions, and the change rule of swelling-shrinkage deformation of red clay was obtained. The results show that the method can realize the dry-wet cycle test without disassembly, and overcome the defects of the dry-wet cycle test of soil with zero load. The method can provide more reasonable technical indicators for engineering design. The swelling-shrinkage deformation of red clay under dry-wet cycle cannot be fully recovered, and the overlying load can restrain its expansibility and enhance its shrinkage. When the load is less than 50 kPa, the sample expands, and the greater the compaction degree and the smaller the initial moisture content, the stronger the swelling. When the load is more than 100 kPa, the sample shrinks, and the smaller the compaction degree and the greater the initial moisture content, the stronger the shrinkage. The first wet-dry cycle has the most significant effect on the swelling-shrinking characteristics of red clay. The swelling-shrinking curve becomes more and more gentle with the increase of the number of dry-wet cycles, and the swelling-shrinking characteristics of the sample tend to be stable.