基于昼夜温度变化的混凝土衬砌渠道冻胀有限元分析

为了掌握衬砌渠道冻胀量及冻胀力随昼夜气温变化的发展规律及冻胀破坏极限状态，根据冻土力学及冻土物理学理论，利用有限元软件ANSYS按瞬态温变模式加载温度，对衬砌渠道冻胀过程进行数值模拟，研究了其温度场和冻胀变形及法向冻胀力与切向冻胀力随时间的变化规律。结果表明：渠道冻融破坏除因渠基土冻胀外，阴阳两坡的温度、冻胀变形、冻胀力既不均匀不对称变化又不同步，也是渠道冻胀破坏的重要原因；阳坡滞后阴坡约15 d冻结，最大冻胀量及最大冻胀力滞后日平均最低气温约4 d，日内最大冻胀量及最大冻胀力滞后日最低气温约1 h；模拟结果与野外观测资料基本吻合，但比稳态数值模拟结果偏大，表明了运用瞬态数值模拟进行渠道抗冻胀设计的正确性和合理性。

Finite element analysis of the concrete lining channel frost heaving based on the changing temperature of the whole day

In order to find out the developing regularity of frost heaving pressure and frost heaving deformation of concrete lining changed with temperature in the daytime and at night, basing on the mechanics and the theory of physics of the frozen soil, using ANSYS to do numerical simulation of the frost heaving process of the concrete lining, loading the temperature by the transient temperature change mode, this paper researches the temperature field and frost heaving distortion and changing rule of the normal frost heaving pressure and the tangential frost heaving pressure with the time. The results showed that the causes of the frozen and thawing destruction of the canal included not only the frost heaving of basic soil of the canal, but also the uneven, asymmetric, asynchrony changes of temperature, frost heaving deformation and frost heaving pressure at the two slopes of the canal. Soil of shady slope was frozen about 15 days earlier than that of sunny slope, the maximum frost heaving pressure and frost heaving amount appeared about 4 days later than the daily average lowest temperature, the maximum frost heaving pressure and frost heaving amount in one day appeared no more than 1 hour later than the daily lowest temperature. The results agree well with those of local test, but were bigger than those of the firm form numerical simulation, which indicates that using transient numerical simulation to design the canal preventing frost heaving is correct and rational.