中文摘要：

为了获得恒定初始状态下膨胀土膨胀量随上覆荷载的变化规律，为膨胀土湿胀数学模型的建立提供基础，针对常规有荷膨胀试验中施加上覆荷载后会导致试样压缩和初始干密度发生变化的问题，改进试验装置，分别选取强、中、弱3种膨胀土进行了改进和常规膨胀土有荷膨胀对比试验。研究结果表明，常规有荷膨胀试验中不同的上覆荷载作用会使试样初始干密度增加1％～3％，吸水恢复到初始干密度状态后含水率会增加20％～30％；改进的有荷膨胀试验因避免了初始干密度的增大，使测试结果小于常规试验结果，得到的膨胀土湿胀变形公式中的回归参数n值比常规方法中使用的”值小29％～66％。

英文摘要：

In order to observe the variation of the expansive soil swelling deformation with upper load and provide the basement for the modelling of swelling deformation, an improved testing device was proposed to avoid the compression and variation of the initial dry density because of the upper load in the common loaded swelling test. The comparison tests between the common and the improved were conducted between three kinds of expansive soils. The results show that different upper loads in the common method can occur 1-3 % increase in initial dry density of soil samples, 20 % - 30 % increase in moisture content when the dry density recover to the initial one. In the improved method, the dry density can remain the initial value during the whole testing, the loaded swelling ratio obtained by the improved method is smaller than the value obtained by the common method, the regression parameters used in the predicted swelling deformation are 29% -66% smaller than that used in the common method.