| 摘要: |
| 南水北调南阳段膨胀土位于季节性冻土区域，易受冻融循环的影响。以南阳膨胀土为研究对象，对不同含水率、冻结温度、冻融循环次数的膨胀土试样进行变形测量和无侧限压缩试验。试验发现，含水率对膨胀土力学性质影响较大，含水率越高，强度与弹性模量衰减量越大；冻结温度对试样体积有较大影响，尤其是-10 ℃。根据显著性分析理论，研究含水率、冻结温度、冻融循环次数以及各因素间交互作用对膨胀土物理力学性质影响的显著性。结果表明，含水率对膨胀土力学性质影响最明显，含水率和冻结温度间的交互作用对强度影响较为显著；冻结温度对膨胀土体积变化影响最大，含水率和冻融循环次数的交互作用对体积变化有一定影响。在研究冻融循环条件下膨胀土物理力学性质时，不仅要考虑单一因素的影响，还应综合考虑各种因素交互作用的影响。 |
| 关键词: 膨胀土 冻融循环 应力应变曲线 强度 弹性模量 体积变化 显著性分析 |
| DOI： |
| 分类号:TU443 |
| 基金项目:江苏省普通高校研究生实践创新计划项目（SJZZ16_0082） |
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| Experimental studies on freeze-thaw cycles of expansive soil based on orthogonal design |
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SONG Yingjun1, XU Lei1, LU Yang1, QIAN Zhiyu2, ZHANG Yuzhuo3, LI Jianping1
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1.College of Water Conservancy and Hydropower, Hohai University, Nanjing;2.School of Hydraulic Energy and Power Engineering, Yangzhou University, Yangzhou;3.Shanghai Municipal Engineering Design Institute (Group) Co., Ltd., Shanghai
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| Abstract: |
| The expansive soil in the Nanyang section of the South-to-North Water Diversion Project is situated at the seasonal frozen soil region, which is easy to be affected by the freeze-thaw cycles. The freeze-thaw cycles will also change the structures of the expansive soil and affect its physical and mechanical properties, which will make a notable impact on the construction of the works. In order to study the factors and interactions on the physical and mechanical properties of the expansive soil, the Nanyang expansive soil was taken as a case study. The deformation measurements and unconfined compressive tests were carried out for understanding the physical and mechanical properties of the Nanyang expansive soil samples under the conditions of different water contents, freezing temperatures and freeze-thaw cycles. The testing results show that the water content has a great influence on the mechanical properties of the expansive soil: the higher the water content, the greater the strength and elastic modulus decline. The freezing temperature has a great influence on the volume change, especially -10 ℃. Some studies of the significant influence of the water content, freezing temperature, the number of freeze-thaw cycles as well as the interaction between different factors on the physical and mechanical properties of the expansive soil were made on the basis of the theory of significance analysis. The study results show that the impact of the water content on the mechanical properties of the expansive soil is the most remarkable, and the interaction between the freeze temperature and water content has a significant impact on the unconfined compressive strength. And the freezing temperature is the most significant influence on the volume change, and the interaction between the water content and freezing-thaw cycles has a certain influence on the volume change. Therefore, we should not only consider the influences of a single factor, but also consider the interactions of various factors in studying the physical and mechanical properties of the expansive soil under the conditions of the freeze-thaw cycles. |
| Key words: expansive soil freeze-thaw cycles stress-strain curves strength elastic modulus volume change significance analysis |
