不同含水率粘土在不同试验条件下的应力-应变特性

Stress-strain behaviour of clay with different water contents under different test conditions

采用单轴固结试验和三轴剪切试验对饱和、湿润、风干以及烘干的藤森粘土进行了应力-应变特性研究。在试验过程中,进行了不同轴向应力水平下的恒应变率加载试验、蠕变试验以及卸载与重复加载试验。局部变形测量传感器(LDT)被用于三轴剪切试验中的轴向变形测量以提高小应变测量的精度。试验结果表明,不同含水率与饱和度的藤森粘土在单轴固结试验与三轴剪切试验条件下都表现出明显的粘塑性。它们的加载速率效应、蠕变效应都相似;而且在蠕变结束后的一小段邻域内藤森粘土的强度有明显的提高。笔者提出用参数β来描述藤森粘土的粘性。对试验结果的计算分析表明,在单轴和三轴试验条件下不同含水率与饱和度的藤森粘土的β值介于0.034到0.064之间;而且,含水率高的藤森粘土的β值大于含水率低的藤森粘土的β值,单轴试验条件下的β值大于三轴试验条件下的β值。

Stress-strain behaviour of saturated, wet, air-dried and oven-dried Fujinomori clay was evaluated by performing a series of one dimensional （1D） compression and triaxial compression （TC） tests including primary loading, global unloading and reloading, In the tests, axial strain rate was changed stepwisely many times during monotonic primary loading with a constant strain rate, Creep fest was also performed during primary loading, Local displacement transducer （LDT） was used in the triaxial compression tests to improve the accuracy of the measurement of vertical strain. In order to evaluate the visco-plastic properties of Fujinomori clay, parameter β was introduced according to the present test results of clay and authors＇ previous study. It was shown that viscous property was generally larger in saturated clay than in dried clay; and larger in one dimensional compression tests than in triaxial compression tests,