| 庞旭卿,胡再强,李宏儒,焦黎杰.黄土剪切损伤演化及其力学特性的CT-三轴试验研究[J].水利学报,2016,47(2):180-188 |
| 黄土剪切损伤演化及其力学特性的CT-三轴试验研究 |
| Structure damage evolution and mechanical properties of loess by CT-triaxial test |
| 投稿时间：2015-03-15 |
| DOI：10.13243/j.cnki.slxb.20150297 |
| 中文关键词: 黄土 细观结构 损伤 力学特性 CT-三轴试验 |
| 英文关键词: loess meso-structure damage mechanical characteristics CT-triaxial test |
| 基金项目:国家自然科学基金项目(50778152);陕西省渭南市科研发展计划项目(2015KYJ-3-2);陕铁院科研基金(2015-09) |
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| 中文摘要: |
| 利用应力控制式CT-三轴仪研究了非饱和Q3 原状黄土与扰动黄土三轴剪切变形特性,并利用CT 技术对其内部结构变化进行了无损量测,得到内部结构演化的CT图像和相应的CT数据,从细观上解释了结构性黄土三轴剪切破坏细观结构演化规律。结果表明:随围压的增大,黄土三轴剪切偏应力轴应变关系曲线由弱软化型逐渐转变为弱硬化型,原状黄土的体应变无论是剪缩还是剪胀均大于扰动黄土。剪切变形呈应变弱软化型黄土平均CT数与轴向应变关系曲线先经历一个小幅增长后逐渐减小。剪切变形呈应变弱硬化型黄土平均CT数与轴向应变关系曲线在剪切初期快速增长,随后在剪切过程中缓慢增长。扰动黄土剪切破坏过程中试样中部相比全区剪切破损较小,裂纹主要在试样外围衍生;原状黄土胶结区表现为逐渐破损,空洞区由于周围土颗粒的滑移而逐渐被压密。CT 技术使土的细观结构研究达到定量阶段,为建立土的结构演化方程和结构性本构模型提供了试验基础。 |
| 英文摘要: |
| A series of CT-triaxial tests of an intact unsaturated Q3 loess and remolded loess were conducted using a stress controlled CT multi-function triaxial apparatus developed, and the changes of the internal structure was measured using CT technology, The distinctive CT images and detailed CT data were obtained during nondestructive of the loess, which explains meso-structure evolution of loess under triaxial shear failure conditions from the microscopic view. The results show that, With the increase of confining pressure, the curves of relationship between meridional stress and axial strain transformed into hardening from weak softening gradually, The curves of relationship of shear failure strain softening between body strain and axial strain transformed into contraction form from dilatation. The curves of relationship between CT number and average axial strain experience a slight increase first, then reduce gradually. The relation curves between average CT number and the axial strain of shear failure strain hardening type increase rapidly in the initial stage, and then slow growth in the shearing process. The failure process of remolded loess shear specimen in central shear damage smaller,crack mainly derived in the periphery of the samples. The performance of intact loess cementation zone gradually broken, empty area showed due to the slip granular soil around and gradually by compression. CT technology makes the soil meso-structure research to a quantitative stage, and provides the experimental basis for establishing the constitutive model of soil structure and structural evolution equations. |
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