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冰川冻土 ›› 2016, Vol. 38 ›› Issue (4): 1142-1149.doi: 10.7522/j.issn.1000-0240.2016.0133

• 寒旱区重大工程问题 • 上一篇    下一篇

干湿和冻融循环作用下黄土强度劣化特性试验研究

李丽1, 张坤1, 张青龙1, 毛云程1, 李国玉2   

  1. 1. 甘肃省交通科学研究院有限公司, 甘肃 兰州 730070;
    2. 中国科学院 寒区旱区环境与工程研究所 冻土工程国家重点实验室, 甘肃 兰州 730000
  • 收稿日期:2015-10-13 修回日期:2016-07-29 出版日期:2016-08-25 发布日期:2016-09-19
  • 作者简介:李丽(1986-),女,新疆昌吉人,工程师,2013年在长安大学获硕士学位,现从事岩土力学与工程相关工作.E-mail:lily_er@163.com
  • 基金资助:
    冻土工程国家重点实验室开放基金项目(SKLFSE201107);甘肃省科技重大专项计划项目(143GKDA007);中国科学院西部之光重点项目(李国玉)资助

Experimental study on the loess strength degradation characteristics under the action of dry-wet and freeze-thaw cycles

LI Li1, ZHANG Kun1, ZHANG Qinglong1, MAO Yuncheng1, LI Guoyu2   

  1. 1. Gansu Transportation Research Institute Co., Ltd., Lanzhou 730070, China;
    2. State Key Laboratory of Frozen Soil Engineering, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China
  • Received:2015-10-13 Revised:2016-07-29 Online:2016-08-25 Published:2016-09-19

摘要: 通过室内试验模拟土体季节性的干湿和冻融交替变化,采用直剪试验测试了原状黄土经干湿和冻融循环作用后的抗剪强度及抗剪强度参数的变化,并进行了直剪后试样的易溶盐总量测定.结果表明:干湿和冻融循环作用对原状黄土物理力学性质影响极大,是造成黄土边坡破坏的主要因素.随着干湿循环次数的增加,试样的抗剪强度逐渐减小,黏聚力逐渐减小,内摩擦角先增加,后逐渐趋于稳定,盐分迁移现象明显,土样下部易溶盐含量逐渐减少,上部易溶盐含量逐渐增加,并且试样的质量损失逐渐增加;随着冻融循环次数的增加,试样的抗剪强度逐渐减小,黏聚力逐渐增大最后趋于稳定,而内摩擦角和盐分迁移现象不明显.

关键词: 干湿循环, 冻融循环, 强度劣化, 直剪试验, 易溶盐

Abstract: Laboratory experiments were used to simulate the soil seasonal dry-wet and freeze-thaw alternate changes. Using direct shear test to measurement the change of the shear strength and parameters of undisturbed loess after dry-wet and freeze-thaw cycles, and determine the sample total soluble salts after direct shear test. The results showed that: dry-wet and freeze-thaw cycles has a great influence on physical and mechanical properties of undisturbed loess, is the main factor of the loess slope failure. With the increase of dry-wet cycles, the shear strength of the sample decreases, the cohesive force is gradually reduced, internal friction angle first increases, then gradually stabilized, salt migration phenomenon obviously, the lower part of soil soluble salt content gradually reduce, the upper soluble salt content gradually increases, and the mass loss of the sample increased. With the increase of freeze-thaw cycles, the shear strength of the sample decreases, the cohesive force is gradually increased, then gradually stabilized, but the internal friction angle and salt migration phenomenon not obviously.

Key words: dry-wet cycles, freeze-thaw cycles, strength degradation, direct shear test, soluble salts

中图分类号: 

  • P642.13+1