| 冻融循环对粉砂土动力特性影响的试验研究 |
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| 引用本文： | 孙静,公茂盛,熊宏强,甘霖睿.冻融循环对粉砂土动力特性影响的试验研究[J].岩土力学,2020,41(3):747-754. |
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| 作者姓名： | 孙静 公茂盛 熊宏强 甘霖睿 |
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| 作者单位： | 1. 黑龙江大学 建筑工程学院，黑龙江 哈尔滨 150080；2. 中国地震局工程力学研究所，黑龙江 哈尔滨 150080 |
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| 基金项目： | 国家自然科学基金项目资助（No.51678541，No.51108163）；中国地震局工程力学研究所基本科研业务费专项资助项目（No.2016A01）。 |
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| 摘 要： | 借助GDS动三轴试验研究了不同负温下经历多次冻融循环后粉砂土的动应力、动模量、动模量比和阻尼比等动力参数的变化规律。试验发现,相同动应变下,冻融循环与动应力和动模量呈负相关性,而与动模量比和阻尼比呈正相关性,随着冻融次数增加,动应力和动模量都减小,动模量比和阻尼比都增大,通过回归分析分别给出了动模量比与动应变关系曲线和阻尼比与动应变关系曲线的归一化拟合模型。冻融循环对初始动模量和最大阻尼比影响显著。随着冻融次数增加,初始动模量减小,而最大阻尼比增大。分别对不同负温下冻融次数对初始动模量和最大阻尼比的影响进行了回归分析,提出了冻融次数修正系数的计算公式。结果表明,温度越低冻融循环对粉砂土动力特性影响越明显,经历5次冻融循环后的动力参数相对稳定,建议将5次冻融循环后的动力参数作为基本参数进行动力反应分析计算。
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| 关 键 词： | 冻融循环 粉砂土 动力特性 动模量 阻尼比 |
| 收稿时间： | 2019-04-16 |
| 修稿时间： | 2019-07-29 |
Experimental study of the effect of freeze-thaw cycles on dynamic
characteristics of silty sand |
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| SUN Jing,GONG Mao-sheng,XIONG Hong-qiang,GAN Lin-rui.Experimental study of the effect of freeze-thaw cycles on dynamic
characteristics of silty sand[J].Rock and Soil Mechanics,2020,41(3):747-754. |
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| Authors: | SUN Jing GONG Mao-sheng XIONG Hong-qiang GAN Lin-rui |
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| Institution: | 1. School of Civil Engineering, Heilongjiang University, Harbin, Heilongjiang 150080, China;
2. Institute of Engineering Mechanics, China Earthquake Administration, Harbin, Heilongjiang 150080, China |
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| Abstract: | By using the GDS dynamic triaxial apparatus tests, the effect of freeze-thaw cycles on dynamic stress, dynamic modulus, dynamic modulus ratio and damping ratio of silty sand under different negative temperatures has been investigated in this study. It is found that under the same dynamic strain, the freeze-thaw cycles are negatively correlated with dynamic stress and dynamic modulus, but positively correlated with dynamic modulus ratio and damping ratio. With the increasing of freeze-thaw cyclic numbers, the dynamic stress and dynamic modulus decrease while the dynamic modulus ratio and damping ratio increase. The normalized fitting models for the dynamic modulus ratio versus the shear strain and the damping ratio versus the shear strain have been presented by regression analysis. The freeze-thaw cycles have a significant effect on the initial dynamic modulus and the maximum damping ratio. With the increasing of freeze-thaw cyclic numbers, the initial dynamic modulus decreases and the maximum damping ratio increases. The effects of freeze-thaw cycles on the initial dynamic modulus and the maximum damping ratio under different negative temperatures have also been analyzed, and the calculation formulae of the number of freeze-thaw cycles correlation coefficients have been given. The results indicate that the effect of freeze-thaw cycles on dynamic characteristics of silty sand is obvious with decreasing of the temperature, and the dynamic characteristics after five freeze-thaw cycles are relatively stable. It is suggested that the dynamic parameters after five freeze-thaw cycles can be used as the basic parameters for the dynamic response analysis. |
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| Keywords: | freeze-thaw cycles silty sand dynamic characteristics dynamic modulus damping ratio |
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