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石英砂剪切带内部结构演化特征的环剪试验研究

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滑坡的宏观力学特性往往受滑带内部微观结构的影响,因此深入研究滑带内部微观结构的演变规律对于滑坡研究具有重要意义.通过石英砂环剪试验,模拟了剪切作用下颗粒状滑带的形成演化过程,利用CT扫描成像系统及图像处理技术,定量分析剪切带内部结构演变特征.研究结果表明:随着剪切位移增大,颗粒破碎导致剪切带内细颗粒逐渐增多,最终形成上下层细颗粒较少,核心层细颗粒富集的3层剪切带结构;剪切位移达到25 m时,细小颗粒在核心层两侧边界聚集形成细颗粒带,越靠近核心层边界细颗粒占比和颗粒磨圆度越大;剪切位移增大至100 m时,细颗粒带内形成2层连续发育细颗粒聚集的剪切滑动面.以上发现对于深入理解滑带的形成演化机制及内部结构的演变规律具有十分重要的意义.
Investigating the evolution of shear zones through ring shear tests on quartz sand
The macroscopic mechanical properties of landslides are often influenced by the microstructure of the shear zone.Therefore,it is important to study the microstructural evolution of the shear zone to better understand the nature and occurrence of landslides.In this study,we simulated the formation and evolution of shear zones by using the ring shear test on coarse quartz sand.We used X-ray computed tomography scanning and image analysis to quantitatively analyze the internal structural characteristics of the shear zone.The results showed that with increasing shear displacement,particle fragmentation led to a gradual increase in the number of fine particles within the shear zone.A three-layer structure was observed after shearing:upper and lower layers,and a core layer.The upper and lower layers had fewer fine particles than the core layer,which had a high concentration of them.After a shear displacement of 25 m,the accumulation of fine particles led to the formation of fine particle layers along the boundaries of the core layer.Furthermore,there was an increasing ratio of fine particles in the core layer and a corresponding enhancement in particle roundness when approaching the boundary.When the shear displacement was 100 m,shear surfaces were observed within the fine particle layers,indicating that the shear behavior of the particles of quartz sand was primarily concentrated on these surfaces.These findings had significant implications for our understanding of the formation and internal structural evolution of shear zones.

landslideshear zonering shearquartz sandCT scanning

高欣、李延、黄之辉、周力、赵建军

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地质灾害防治与地质环境保护国家重点实验室(成都理工大学),成都 610059

滑坡 滑带 环剪试验 石英砂 CT扫描

2024

成都理工大学学报(自然科学版)
成都理工大学

成都理工大学学报(自然科学版)

CSTPCD北大核心
影响因子:1.596
ISSN:1671-9727
年,卷(期):2024.51(2)
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