摘要
研究黄土在循环荷载下的动力学特性,是探讨黄土地区相关工程问题的关键,对于相应地区基础设施的建设具有现实意义。文中以西吉县夏家大陆地区的黄土作为研究对象,研究不同含水率、固结应力比、振动频率以及围压对黄土动剪切模量和阻尼比的影响,并结合扫描电子显微镜观察振动加载后土样,从微观角度解释引起黄土动力特性变化的原因。结果表明:动剪切模量随动剪应变的增大而逐渐减小,用对数函数可以拟合二者之间的关系;动剪切模量随含水率的增大而减小,随固结比、加载频率和围压的增大而增大;阻尼比随含水率的增大呈现增大的趋势,随着固结比和围压的增大而呈现减小的趋势,围压对其影响不明显;通过PCAS分析系统计算对比不同试验条件下土样概率熵、平均形状系数、分形维数的差异,可以对黄土动力特性的变化规律做出合理的解释。
Studying the dynamic characteristics of loess under cyclic loading is the key to discussing actual engineering problems in the loess area, and has practical significance for the construction of infrastructure in the corresponding area. In this paper, the loess in the Xiajia mainland area of Xiji county was used as the research object to study the effects of different moisture content, consolidation stress ratio, vibration frequency and confining pressure on the dynamic shear modulus and damping ratio of loess, and combine the scanning electron microscope to observe the soil samples after vibration loading, and to explain the reasons for the changes in the dynamic characteristics of loess from a microcosmic view. The results show that the dynamic shear modulus gradually decreases with the increase of the dynamic shear strain, and the logarithmic function can be used to fit the relationship between the two;the dynamic shear modulus decreases with the increase of the water content, and increases with the consolidation ratio, loading frequency and confining pressure increase. The damping ratio shows an increasing trend with the increase of water content, and shows a decreasing trend with the increase of consolidation ratio and confining pressure. The influence of confining pressure on it is not obvious. The difference of probability entropy, average shape coefficient and fractal dimension of soil samples under different test conditions can be calculated and compared by the PCAS analysis system, which can make a reasonable explanation for the dynamic characteristics of loess.
作者
李帅
王家鼎
李承霖
苏昱博
LI Shuai;WANG Jiading;LI Chenglin;SU Yubo(State Key Laboratory of Continental Dynamics,Department of Geology,Northwestern Univ,Xi'an 710069;School of Physics Northwestern University,Xi'an 710069,China)
出处
《干旱区资源与环境》
CSSCI
CSCD
北大核心
2021年第12期142-149,共8页
Journal of Arid Land Resources and Environment
基金
国家自然科学基金重大科研仪器研制项目(42027806)
国家自然科学基金重大项目(41630639)
国家重点研发计划(2018YFC1504703)资助。
关键词
地质工程
循环荷载
动剪切模量
阻尼比
微观结构
geological engineering
cyclic loads
dynamic shear modulus
damping ratio
micro structure
