兰州大学机构库 >土木工程与力学学院
含盐冻结粉质砂土三轴抗压强度试验研究
Alternative TitleExperimental Study on Triaxial Compression Test of Saline Frozen Silty Sand
胡凯
Thesis Advisor赖远明
2015-05-23
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name硕士
Keyword围压 含盐量 温度 纳米二氧化硅 强度准则
Abstract冻土的力学性质受含水量、含盐量、有机质含量、温度、应变速率、围压和应力应变历史等条件的影响。对冻土力学性质的研究主要分为试验研究和理论研究两大类。然而,由于冻土自身性质的复杂性和外部条件的多样性,需要对冻土力学性质开展进一步的研究。 本文先对天然含盐、经洗盐和配置不同硫酸钠盐分量(0.5%、1.5%、2.5%)的冻结粉质砂土,在温度-2℃、-4℃、-6℃,围压范围为0.3MPa~18MPa的条件下进行三轴压缩试验。得到试验曲线为应变软化型,同时通过强度结果分析得到随着围压的增大,三轴抗压强度先增大后减小;随着温度降低,强度增大,且二者在双对数坐标中呈线性关系;随着硫酸钠含量的增大,强度先减小后增大。 然后对掺入1%纳米二氧化硅含量的冻结粉质砂土进行温度-2℃,围压为0.3MPa~18MPa的三轴压缩试验。得到其试验曲线也为应变软化型,可以利用修正的Duncan-Chang双曲线模型很好的拟合其应力应变曲线;其强度相对于未掺纳米二氧化硅冻结粉质砂土有很大的提高;并对修正的Duncan-Chang双曲线模型求微分得到其初始弹性模量随围压的变化可以分为三个阶段。 最后,根据上述的得到的试验结果,利用前人的研究成果和最小二乘法,得到指数型和二次抛物线强度准则,对其强度变化进行很好的预测。
Other AbstractMechanical properties of frozen soli are affected by moisture, salt content, organic matter ,temperature, strain rate, confining pressure,stress and strain history. Study of the mechanical properties of frozen soil is divided into two categories:experimental and theoretical study. However, due to the complexity of permafrost and the diversity of the nature of external conditions, we need to conduct a further study for mechanical properties of frozen soil. The first of this thesis was conducting triaxial compression tests at a confining pressure range of 0.3MPa ~ 18MPa at a temperature of -2 ℃, -4 ℃, -6 ℃ for the natural state of salinity soil, the salt washed soil and the configured salt washed soil with different soil containing sodium salt content (0.5%, 1.5%, 2.5%) of frozen silty sand.We obtained the test curve was strain softening style,at the same time through the analysis of strength results,we obtained that as the confining pressure increasing,the trixial compressive strength was first increasing the decreasing;As the temperature decreasing, the strength was increasing, and they showed a linear relationship in a double logarithmic coordinates; As sodium content increasing, the strength was first decreasing then increasing. Then this thesis was conducting triaxial compression tests at a confining pressure range of 0.3MPa ~ 18MPa at a temperature of -2 ℃ for frozen silty mixed with 1% of nano silicon dioxide content.we obtained its test curve was strain softening style, and we can take advantage of the modified Duncan-Chang hyperbolic model fit well with the stress-strain curve; With respect to undoped nano silicon dioxide frozen silty sand, its strength have a significant growth; And through differentiating for modified Duncan-Chang hyperbolic model , we obtained the variation of initial modulus with the confining pressure can be divided into three stages. Finally, according to the test results of the above, using the predecessors'''' research results and the least square method, we obtained a exponential strength criterion and a parabola strength criterion, and it can predict its intensity very well.
URL查看原文
Language中文
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/226380
Collection土木工程与力学学院
Recommended Citation
GB/T 7714
胡凯. 含盐冻结粉质砂土三轴抗压强度试验研究[D]. 兰州. 兰州大学,2015.
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