原状黄土变形与强度特性的加载速率效应

发布时间：2018-05-02 06:34

本文选题：道路工程 + 加载速率效应　；参考：《中国公路学报》2016年07期

【摘要】：为揭示荷载施加快慢对土体变形与强度特性的影响规律,基于三轴CU试验,开展了不同围压和含水率状态下,原状和重塑黄土加载速率效应的试验研究。在试验结果基础上,分析了加载速率对黄土应力-应变曲线特征、抗剪强度以及结构强度等的影响规律。研究结果表明:加载速率对黄土的应力-应变曲线形态有显著影响,高加载速率、低围压、低含水率可以导致应变软化现象的产生;加载速率对剪切强度的影响存在临界值,加载速率小于此值时抗剪强度随着加载速率的增大而增大,超过此值时抗剪强度又有一定程度的降低,呈现先增后减的特征;加载速率对抗剪强度参数c和φ的影响规律不尽相同:黏聚力c随着加载速率的增大呈现先增大后减小的规律,而内摩擦角φ则随着加载速率的增大单调递减;加载速率对黄土结构强度的影响规律与抗剪强度基本一致,亦存在一临界加载速率,结构强度随着加载速率的增大也表现出先增大后减小的规律。
[Abstract]:In order to reveal the influence of loading speed and speed on the deformation and strength characteristics of soil, based on triaxial CU test, the loading rate effect of undisturbed and remolded loess was studied under different confining pressure and moisture content. Based on the experimental results, the effects of loading rate on the stress-strain curve, shear strength and structural strength of loess are analyzed. The results show that the loading rate has a significant effect on the stress-strain curve shape of loess, high loading rate, low confining pressure and low moisture content can lead to strain softening, and the influence of loading rate on shear strength has a critical value. When the loading rate is smaller than this value, the shear strength increases with the increase of the loading rate, and when the loading rate exceeds this value, the shear strength decreases to a certain extent, showing the characteristics of first increasing and then decreasing. The effect of loading rate on shear strength parameters c and 蠁 is different: the cohesive force c increases first and then decreases with the increase of loading rate, while the internal friction angle 蠁 decreases monotonously with the increase of loading rate. The effect of loading rate on the structural strength of loess is basically consistent with that of shear strength, and there is a critical loading rate, and the structural strength increases first and then decreases with the increase of loading rate.
【作者单位】：长安大学国土资源部岩土工程开放研究实验室;长安大学地质工程与测绘学院;
【基金】：国家自然科学基金项目(41372327)
【分类号】：U416.1

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