应变累积对黏土动剪模量和阻尼比影响的试验研究

Experimental study on effect of shear strain accumulation on dynamic shear modulus and damping ratio of clay soil

通过对比试验,研究了分级循环加载试验中的应变积累现象,分析其对土动剪模量和阻尼比的影响,并指出:由于剪切应变的积累,分级循环加载试验得出的滞回曲线随着加载级数的增加,而沿着剪应变轴逐渐发生平移,但其形状特性并未发生变化。讨论了分级加载试验数据处理的方法,试验结果表明:先前的较小幅值荷载作用下产生的累积应变对后继较大幅值荷载下测得的动剪模量和阻尼比影响较小。最后,分析了分级循环加载试验方法的意义。

The phenomena of strain accumulation in the specimen when tested by graded loading is studied through two group of comparative experiments, and then the influence of this phenomena on the dynamic shear modulus and damping ratio of the soil is analyzed. It is pointed out that because of the accumulation of shear strain, the hysteresis loops gained by graded loading method will shift along the shear strain axis as soon as the load grade number increases, while at the same time, the shape character of those loops will keep unchanged. The method of how to deal with the original data produced by the graded loading test is discussed. According to the results of the comparative experiments, it is concluded that the shear strain accumulating under comparatively small amplitude loads does little with the dynamic shear modulus and the damp ratio gained by the large graded loading test later. Lastly,the signification of the graded loading test method and its application to the soil dynamics research are discussed.