HUANG Yuansheng, LI Peng, YAN Fuzhang, WANG Yanbing, CHENG Dongxing. 2014: ANALYSIS AND PREDICTION ON LONG-TERM SHEAR STRENGTH OF FROZEN SOIL AND ITS INFLUENCE FACTORS ALONG QINGHAI-TIBET DC TRANSMISSION LINE. JOURNAL OF ENGINEERING GEOLOGY, 22(3): 507-514. DOI: 10.13544/j.cnki.jeg.2014.03.021
    Citation: HUANG Yuansheng, LI Peng, YAN Fuzhang, WANG Yanbing, CHENG Dongxing. 2014: ANALYSIS AND PREDICTION ON LONG-TERM SHEAR STRENGTH OF FROZEN SOIL AND ITS INFLUENCE FACTORS ALONG QINGHAI-TIBET DC TRANSMISSION LINE. JOURNAL OF ENGINEERING GEOLOGY, 22(3): 507-514. DOI: 10.13544/j.cnki.jeg.2014.03.021

    ANALYSIS AND PREDICTION ON LONG-TERM SHEAR STRENGTH OF FROZEN SOIL AND ITS INFLUENCE FACTORS ALONG QINGHAI-TIBET DC TRANSMISSION LINE

    • Permafrost has all kinds of rock and soil with ice under 0℃.Due to its complexity of physical and mechanical properties, problems are brought about for the design and construction of Qinghai Tibet power DC interconnection line project. Especially, the safe operation and stability of power grid within service life are affected by long-term shear strength of frozen soil because the soil properties, ice content and density are complex along the project. To solve these questions, the remolded samples are prepared. Three kinds of frozen soils(silty clay, silty and fine sand),three kinds of ice state(ice saturated, rich ice and muti ice state) at dense and loose conditions are sheared with fast rate by creep tests in laboratory under-2℃.The creep properties of different types of frozen soils are obtained. The long-term strength and its influence factors are predicted and analyzed. The results show that:(1)The load capacity of frozen soils increases in a short time with the increase of ice content; as loading time increases, creep deformation of frozen soils increases and the strength reduces because of the rheological properties of the ice; (2)The initial strength is higher as density and ice content increase; when time increases, intensity attenuation velocity is smaller as density reduces or ice content increases; (3)Variation of long term strength is not affected by the soil types, which shows that different kinds of frozen soils can be handled in the same way if only the long-term strength is considered during construction. The above results provide a basis for frozen soils foundation design, construction and operation of transmission line and reference experimental data for other engineering activities in Qinghai-Tibet area.
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