季节冻土区梯形混凝土渠道冬季停水与过水运行方式对温度场的影响研究

Study on influences from water cut-off and water passing operation modes of trapezoidal concrete canal in seasonal frozen-soil region in winter on temperature field

针对西北地区输水明渠易发生冻胀破坏的问题,依据热传导和水分迁移理论建立冻结期渠基土温度场,以分析渠道内过水对温度场分布的影响为目标,以新疆玛纳斯河四级水电站引水渠为典型案例,应用有限元软件进行温度场的模拟,并将结果与相关文献中的数据及破坏类型进行比对,验证模拟的合理性。结果表明:渠道内是否过水对渠道的温度场有显著的影响,主要是其温度场的分层发生变化且其温度线也出现了强烈波动。经实地观察发现,输水明渠渠基土体易产生较大的冻胀变形导致衬砌板胀裂、隆起及滑塌等破坏十分严重的位置与模拟中温度场发生变化的位置基本一致,且满足误差要求。用冻结期渠基土温度场变化来预测输水明渠发生冻胀破坏的准确位置具有很大的参考价值。

Aiming at the problem of that frost-heaving damage is prone to occur at the water conveyance open canal in the region of the Northwest China,a foundation-soil temperature field is established according to the theories of thermal conduction and water migration,and then the temperature field is simulated with the relevant finite element software by taking the analysis of the influence from the water conveyance through canal on the distribution of the temperature field as the object and the diversion canal of Manas River IV Hydropower Station as the typical case,moreover,the result is compared with the data and damage types from the relevant literatures,thus the reasonability of the simulation is verified. The result shows that significant influence is there on the temperature field for whether water passes through the canal or not,which is mainly caused by the variation of the stratification of the temperature field and the strong fluctuation of its temperature line. It is found out through the in situ observation that the locations with quite serious damages induced by swelling,protuberating and slumping of the lining caused by the larger frost-heaving deformation that is prone to be produced by the foundation soil mass of the water conveyance open cannal are basically coincided with those locations with the variations of the temperature field in the simulation,and then the relevant error-requirement can be met as well. Predicting the accurate location of frost-heaving damage with the variation of the temperature field of the foundation-soil of the cannal during frozen period has a great referential value.