黄元生, 李鹏, 严福章, 王彦兵, 程东幸. 2014: 青藏直流输电线路冻土长期抗剪强度预测及影响因素分析. 工程地质学报, 22(3): 507-514. DOI: 10.13544/j.cnki.jeg.2014.03.021
    引用本文: 黄元生, 李鹏, 严福章, 王彦兵, 程东幸. 2014: 青藏直流输电线路冻土长期抗剪强度预测及影响因素分析. 工程地质学报, 22(3): 507-514. DOI: 10.13544/j.cnki.jeg.2014.03.021
    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

    青藏直流输电线路冻土长期抗剪强度预测及影响因素分析

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

    • 摘要: 冻土是指0℃以下,含有冰的各种岩石和土壤,由于其复杂的物理力学特性,给青藏直流联网工程的施工和设计带来了很多难题。工程沿线冻土的长期抗剪强度,更是由于土质、含冰量以及密实度分布的复杂特性,影响了其在使用寿命内的安全运营和稳定性。为解决这一工程难题,室内制备重塑试样并在-2℃的温度下对3种土质类型(粉质黏土、粉砂和细砂)、3种含冰量(饱冰、富冰和多冰)的密实和松散冻土进行直剪快剪的蠕变试验,得到了不同土质、含冰量以及密实度类型的冻土剪切蠕变特性,并分析和预测了长期抗剪强度的变化规律和影响因素,结果表明:(1)短时间内冻土承受荷载的能力随含冰量的增加而增大;随着加载时间的延长,冰的流变特性表现出来,使冻土的蠕变变形加大,冻土的强度降低;(2)密实度越大、含冰量越大的冻土,初期强度越高;随着时间的增加,强度开始衰减,且含冰量越大,密实度越小的冻土衰减速度越快;(3)长期强度的变化规律不受土质的影响,说明在工程施工阶段,若单纯考虑长期强度时,只要不同土质冻土保持冻结状态,可同一对待和处理。以上结论为输电线路冻土基础设计、施工和安全运营提供了一定的理论基础,也为在青藏地区开展的其他工程活动提供了可借鉴的试验数据和资料。

       

      Abstract: 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.

       

    /

    返回文章
    返回