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为了揭示原状Q3黄土在加载和湿陷过程中的细观结构变化,将湿陷三轴仪与医用CT机相配套,进行了一系列控制吸力的CT-三轴湿陷试验,不仅得到了加载过程和湿陷过程中的宏观反应曲线,而且得到了相对应的CT扫描图像。结果表明:原状湿陷性黄土具有较强的初始结构性;加载过程中,较大的孔洞先扩展后闭合,小孔洞逐渐闭合;湿陷过程中,大部分孔洞逐渐闭合且断面的密度分布趋于均匀;湿陷过程中大孔洞闭合与否取决于浸水时的应力状态。通过宏细观试验资料的分析,确定了原状湿陷性黄土的结构屈服应力,提出了一个基于CT数均值的结构性参数,分别定义了加载和湿陷过程中的结构损伤变量,研究了它们的变化规律,建立了结构损伤演化方程。
In order to reveal the mesoscopic structure changes of intact Q3 loess during loading and collapsing, a series of CT-triaxial collapse tests to control suction were carried out with collapsible triaxial apparatus and medical CT machine, and not only loading Process and collapse process in the macro-response curve, and got the corresponding CT scan images. The results show that the original collapsible loess has strong initial structure. During the loading process, the larger pores close and expand first, and the smaller pores gradually close. During the collapsing process, most of the pores gradually close and the density distribution of the sections tends to In uniform; collapse process of large holes closed or not depends on the stress state when immersed in water. Based on the analysis of macro and micro test data, the structural yield stress of intact collapsible loess is determined, and a structural parameter based on CT average value is proposed. Structural damage variables during loading and collapsing are defined respectively. The law of change, established the structural damage evolution equation.