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寒季,季冻区光伏支架基础受地基土不均匀冻胀的影响,引起系统发电效率降低,甚至导致上部结构的整体破坏。因此,工程中常应用螺旋桩来抑制这种病害。本文通过进行单向冻结条件下的模型试验,考察多种螺旋桩及光滑桩的冻拔特性,总结温度分布、冻拔位移和轴向上拔力的变化规律。结果表明:1)确定平均冻拔率ηj为表征抗冻拔能力的合理指标,其中半螺旋大叶片桩具有最小平均冻拔率(1.03%),全螺旋桩的平均冻拔率最高;2)冻拔位移与冻深之间存在线性关系,螺旋叶片的布设影响冻拔发展;3)限定桩竖向位移条件下,轴向上拔力与冻深之间存在指数关系。因此,本文研究成果可为季冻区轻荷载工程基础的抗冻拔措施提供参考。
In winter, the foundation of photovoltaic support in seasonal frost area is affected by the uneven frost heave of the foundation soil, causing the power generation efficiency of the system to decrease and even lead to the overall destruction of the superstructure. Therefore, the project often used spiral pile to suppress this disease. In this paper, through the model test under unidirectional freezing conditions, the freezing and drawing characteristics of many kinds of screw pile and smooth pile are investigated, and the variation rules of temperature distribution, freezing displacement and axial pulling force are summarized. The results showed as follows: 1) The average freezing rate ηj was determined to be a reasonable index to characterize the anti-freezing capacity. The semi-spiral large leaf pile had the lowest average rate of freezing (1.03%), There is a linear relationship between freezing displacement and freezing depth, and the placement of helical blades affects the development of freezing extraction. (3) There is an exponential relationship between the axial pull-out force and the freezing depth under the condition of limited pile vertical displacement. Therefore, the research results in this paper can provide references for the anti-freezing measures of light load engineering in seasonal frozen zone.