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温智, 俞祁浩, 张建明, 董盛时, 马巍, 牛富俊, 赵淑萍, 杨振. 青藏直流输变电工程基础冻结强度试验研究[J]. 岩土工程学报, 2013, 35(12): 2262-2267.
引用本文: 温智, 俞祁浩, 张建明, 董盛时, 马巍, 牛富俊, 赵淑萍, 杨振. 青藏直流输变电工程基础冻结强度试验研究[J]. 岩土工程学报, 2013, 35(12): 2262-2267.
WEN Zhi, YU Qi-hao, ZHANG Jian-ming, DONG Sheng-shi, MA Wei, NIU Fu-jun, ZHAO Shu-ping, YANG Zhen. Experimental study on adfreezing bond strength of interface between silt and foundation of Qinghai-Tibetan transmission line[J]. Chinese Journal of Geotechnical Engineering, 2013, 35(12): 2262-2267.
Citation: WEN Zhi, YU Qi-hao, ZHANG Jian-ming, DONG Sheng-shi, MA Wei, NIU Fu-jun, ZHAO Shu-ping, YANG Zhen. Experimental study on adfreezing bond strength of interface between silt and foundation of Qinghai-Tibetan transmission line[J]. Chinese Journal of Geotechnical Engineering, 2013, 35(12): 2262-2267.

青藏直流输变电工程基础冻结强度试验研究

Experimental study on adfreezing bond strength of interface between silt and foundation of Qinghai-Tibetan transmission line

  • 摘要: 土与基础接触面间的冻结强度是评价冻土区基础工程抗拔性能,分析构筑物与冻土相互作用的基础和关键。通过不同含水率和不同温度青藏粉土与混凝土接触面的直剪试验,研究了冻结强度变化规律。结果表明,温度、含水率和法向应力均对冻结强度和冻结强度恢复有显著的影响。冻土沿接触面的剪切滑移会导致冻结强度损失,冰胶结能力的破坏导致接触面黏聚力减小,表面粗糙程度的增加导致内摩擦角增大,内摩擦角增加对冻结强度增加的贡献远远小于黏聚力减小导致的冻结强度降低。由于含水率、温度和法向应力对冻结强度有显著的影响,冻结强度对于评估基础所受的切向冻胀力以及评价基础的冻拔安全性具有重要的意义。但是,现行规范中冻土区基础切向冻胀力设计值主要依据土体冻胀敏感性确定,并未考虑含水率、温度和法向应力的影响,可能导致切向冻胀力设计值与基础实际受到的冻胀力存在较大的差异,引起基础冻胀失稳或经济浪费。

     

    Abstract: The adfreezing bond strength between soils and foundation surface plays an important role in general stability concerns of foundations in frozen ground. A series of laboratory direct shear tests on the adfreezing interface between silt and concrete are performed to understand the mechanical behaviors of the foundation-frozen soil interface. The results show that the temperature, moisture content and normal stress significantly affect the adfreezing strength and its bond healing. The small displacements between foundation and frozen soils may result in dramatically less loss in the adfreezing strength. The breaking of ice bond decreases the cohesion, and the increasing surface roughness results in the increase in the internal frictional angle. The increase in the adfreezing strength due to the increasing internal frictional angle is significantly smaller than the loss of the adfreezing strength resulting from the decrease in cohesion. The adfreezing bond is an important parameter to reasonably design and construct the frozen ground foundation. The temperature, moisture content and normal stress can also affect the tangential frost heave force via the influence on the adfreezing bond. However, the Chinese standard for the foundation design in frozen ground does not consider the influence of these factors, which may lead to the instability of foundation or economic loss.

     

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