西安地区Q2黄土应力-应变-时间关系的试验研究

Experiment on stress-strain-time relationship of Q_2 loess in Xi'an

为了研究黄土地区许多工程现象的本质原因,探讨应力—应变—时间的关系,对西安地区Q2黄土在改造后的固结仪上进行了单轴无侧限蠕变试验。加载方式为分级加载,通过使用坐标平移法处理蠕变曲线后得到应力—应变等时曲线。研究发现Q2黄土在不同的应力水平下表现出不同的蠕变形态,应力—应变等时曲线上有一较明显的拐点,拐点对应的应力即为屈服应力,屈服应力随着含水率的增加而呈指数降低,当应力水平小于屈服应力时,黄土表现为线性粘弹性特性;当应力水平大于屈服应力时,黄土表现为线性粘塑性特性。

In order to study the essence of many engineering phenomenon in loess district and discuss the relationship among stress, strain and time, we have done the uniaxial uneoniined creep tests by means of modified consolidometer using Q2 Loess samples in Xi＇an. Loading manner is grading load, then we obtained stress-strain tautochrone curve by translation of coordinate axis. Several conclusions are drawn by research on the curves. Q2 Loess showed different creep pattern in different stress level. In the stress- strain curve there is a more obvious inflection point which corresponds the yield stress. When the stress level is less than the yield stress, loess shows the linear visco-elastic properties; when the stress level is greater than the yield stress, the loess shows linear visco-plastic properties