文章摘要
朱龙祥, 范昊明, 郭成久, 金丹, 谢立群, 马仁明.冻融作用对原状棕壤抗剪强度的影响[J].水土保持学报,2021,35(2):55~60,67
冻融作用对原状棕壤抗剪强度的影响
Effect of Freeze-thaw Cycles on Shear Strength of Undisturbed Brown Soil
投稿时间:2020-09-15  
DOI:10.13870/j.cnki.stbcxb.2021.02.008
中文关键词: 棕壤  冻融循环  抗剪强度
英文关键词: brown soil  freeze-thaw cycles  shear strength
基金项目:国家重点研发计划项目(2016YFE0202900);国家自然科学基金项目(41601284)
作者单位E-mail
朱龙祥, 范昊明, 郭成久, 金丹, 谢立群, 马仁明 沈阳农业大学水利学院, 辽宁省水土流失防控与生态修复重点实验室, 沈阳 110866 marenming@syau.edu.cn 
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中文摘要:
      为揭示冻融循环作用对棕壤抗剪强度的影响,采集沈阳地区5 cm和25 cm 2个深度原状棕壤(分别为H5和H25)为研究对象,通过室内冻融循环模拟和土壤直剪试验,研究冻融循环次数和土壤含水率对土壤抗剪强度的影响。结果表明:(1)土样含水率越高,初次冻融作用的破坏效果越强,1次冻融循环后,含水率为25%的H5和H25土样黏聚力分别下降50.00%和25.87%;含水率35%的H5和H25土样黏聚力分别下降75.61%和50.77%。15次冻融循环后,含水率10%的H5和H25土样黏聚力分别增加74.36%和60.08%;含水率35%的H5和H25土样黏聚力分别增加14.63%和26.15%。但在2个不同含水率条件下,黏聚力的增大机制不同。(2)含水率为15%,20%,25%条件下,H5和H25土样内摩擦角在多次冻融循环中始终在一定范围内波动,说明这3个含水率下冻融作用对土壤内摩擦角影响具有不确定性。35%含水率的H5和H25土样内摩擦角受冻融作用的影响较小,分别在(18.57°±0.88°)和(12.86°±1.14°)变化。(3)平均抗剪强度主要受土壤含水率影响,随着含水率的增加呈指数函数减小。受黏粒含量影响,含水率低于25%时,H25土样平均抗剪强度高于H5土样;含水率高于25%时,H25土样平均抗剪强度偏低。
英文摘要:
      In order to reveal effects of freeze-thaw cycles on shear strength of brown soil, the undisturbed brown soil from 5 cm and 25 cm depths (H5 and H25, respectively) in Shenyang area were collected. The effects of freeze-thaw cycles and soil water contents on soil shear strength were analyzed through indoor freeze-thaw simulation and direct shear tests in laboratory. The results showed that:(1) The higher soil water content, the stronger damage effect of the first freeze-thaw cycle. After the first freeze-thaw cycle, soil cohesion of H5 and H25 samples with 25% soil water content decreased by 50.00% and 25.87%, respectively; and the soil cohesion with 35% soil water content decreased by 75.61% and 50.77%, respectively. After 15 freeze-thaw cycles, the cohesion of H5 and H25 samples with 10% soil water content increased by 74.36% and 60.08%, respectively; the cohesion of H5 and H25 samples with 35% soil water content increased by 14.63% and 26.15%, respectively. However, the mechanisms of cohesion increasing under two different soil water contents were different. (2) The internal friction angle of H5 and H25 samples with 15%, 20%, and 25% soil water contents fluctuated during the multiple freeze-thaw cycles, indicating that the effects of freeze-thaw cycles on the internal friction angle were complicated and uncertain in the soil water contents. The internal friction of H5 and H25 samples with the soil water content of 35% were hardly affected by freeze-thaw cycles and varied between (18.57°±0.88°) and (12.86°±1.14°), respectively. (3) The average shear strength mainly decreased exponentially with the increasing of soil water contents. Clay content might play important role in average shear strength at different water contents. When the soil water contents were below 25%, the average shear strength of H25 soil samples were higher than that of H5; while soil water contents were above 25%, the average shear strength of H25 were lower.
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