冻融状态和初始含水率对土壤力学性能的影响

发布时间：2018-04-28 06:21

本文选题：土壤 + 土壤含水率　；参考：《农业工程学报》2017年03期

【摘要】：冻融状态影响土壤的抗剪强度从而威胁季节性冻土地区的工程安全、边坡稳定以及土壤流失。通过直剪试验测定了不同冻融状态和初始含水率对青藏地区(S1)和北京地区(S2)土体抗剪强度的影响。结果显示,2种土在未冻和已融状态下的抗剪强度相似,且均随着土含水率的增加而减小,但S1土抗剪强度比S2土大7.5%~9.7%;在冻融状态下,S1土抗剪强度随着土含水率的增加而增大,而S2土则随之减小。S1冻融土抗剪强度在低含水率(≤13.5%)时小于未冻土和已融土,而在高含水率(≥24.5%)时则反之;S2冻融土抗剪强度小于未冻土和已融土。在冻融状态下2种测试土的内摩擦角显著小于未冻土和已融土,而黏聚力整体上则大于未冻土和已融土。与未冻土或已融土相比,2种土在冻融状态下的强度相对较低,宜作为季节性冻土地区工程设计以及土壤流失防治的基本状态。
[Abstract]:The freezing thawing state affects the shear strength of the soil and threatens the engineering safety, slope stability and soil loss in seasonal frozen soil areas. Through direct shear test, the effects of different freezing thawing States and initial water content on the shear strength of the S1 and Beijing area (S2) are measured. The results show that the 2 kinds of soil are in the condition of unfreezing and melting. The shear strength of S1 soil decreases with the increase of soil moisture content, but the shear strength of S1 soil is larger than that of S2 soil. Under freeze-thaw condition, the shear strength of S1 soil increases with the increase of soil moisture content, while S2 soil decreases the shear strength of.S1 freeze-thaw soil under low water content (less than 13.5%), which is less than unfrozen soil and thawing soil, but at high water content. On the contrary, the shear strength of S2 freeze-thaw soil is smaller than that of unfrozen soil and thawing soil. The internal friction angle of the 2 tested soils under freezing thawing is significantly smaller than unfrozen soil and thawing soil, while cohesion is larger than unfrozen soil and thawing soil. Compared with unfrozen soil or thawing soil, the strength of the 2 soils is relatively low in freeze-thaw condition, and should be used as a season. The basic state of engineering design and soil erosion control in permafrost regions.

【作者单位】：中国农业大学水利与土木工程学院;北京市城市河湖管理处;
【基金】：国家自然科学基金重点项目(41230746)
【分类号】：S152.9

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