【作者】 郭利霞；

【导师】 王正中；

【作者基本信息】 西北农林科技大学 ， 水利水电工程， 2007， 硕士

【摘要】 合理利用水资源是世界各国政府和科学家共同高度关注的问题。在解决水资源的对策中,除兴建必要的蓄水、引水工程、扩大水源外,更重要的是节约用水,提高水的利用率,防止水污染等。渠道防渗是节约用水、实现节水型社会的重要内容。但是,由于对衬砌体抗冻胀问题认识不透,设计上的不合理性及施工质量差等原因,渠道衬砌冻胀破坏屡见不鲜,可以说,渠道衬砌冻害遍及所有季节冻土区,解决这一问题的关键就是要搞清楚刚性衬砌体在受冻胀时的受力情况,作为渠道设计的依据。1)根据渠道冻胀的基本规律、破坏特征提出梯形和准梯形渠道冻胀的力学模型,该模型只有一个待定参数—最大冻结力,只要根据经验或试验确定了该参数,力学模型就可以求解,为其他力学模型的建立提供了一条思路;2)将冻土和衬砌体视为一整体结构,按横观各向同性冻土介质应用有限元方法对衬砌渠道温度场和应力场及变形场进行分析研究,模拟结果与野外观测资料基本吻合,表明渠道冻胀的二维有限元数值模拟能够为季节冻土区渠道工程设计及力学计算提供参考和科学依据;3)对比研究数值模拟与简化力学模型结果,其冻胀变形,冻胀力的分布规律基本一致,也验证了简化力学模型的正确性;4)梯形断面形式的法向冻胀力呈上小下大规律分布,在渠底则趋于均布,而切向冻胀力沿坡面呈上小下大的规律,在渠底几乎趋于零;准梯形渠道断面分布规律与梯形相似;5)准梯形断面主要变形是衬砌体整体随着基土向上抬升,变位比较均匀,而梯形断面渠道冻胀变形不均匀系数显然是比较大的,特别是梯形渠道渠底部分;准梯形断面渠道的整体受力比较小,其中最大拉应力在阳坡的衬砌表面,最大值为15.3 MPa ,而梯形渠道最大拉应力则达到61.5 Mpa,由此可见,准梯形渠道断面的冻胀变形、冻胀力及拉应力都比相同尺寸,相同参数情况下梯形断面的数值小,抗冻胀能力优越于梯形渠道。更多还原

【Abstract】 The problem of using water resources reasonably is drawing government and scientists of attention in the world. In the processing of resolving water resources, besides the water storage engineering and the water diversion engineering should be built and the water resources should be enlarged necessarily, the more important problem is saving the water, increasing the utilization ratio of water,preventing the pollution of water and so on .The seepage control of canal is the important measure of saving water. But,But, because people don’t know enough about this problem or design channel irrationally and so on, channel damage is continue ,one way to solve the problem is to accept force condition , as the basis of channel designing.Firstly, the mechanics models of frost heaving damage of the concrete lining plates of the canal with trapezoidal section and similar trapezoidal section can be solved provided that ad freezing forces is determined according to the practical experience or experiment. At the same time, this can provide some method for other section;Secondly, looking upon frozen ground and the lining step body as one entirety structure , with the application of numerical simulation , ,the paper simulates the frost heaving process of canal, and has a deeply study on its temperature field、the stress and the deformation field.The theoretical analysis results agree well with the local test, that’s to say, the FEM numerical simulation of heaved channel would provide theoretical base for channel engineering design and mechanics calculation in seasonal frozen soil area;Thirdly, compared the result of numerical and that of Mechanics model, the distribution of deformation and frozing force is similar, which also verifies the correctness of the Mechanics model;Forthly, frost-heave vertical forces of trapezoidal canal is small in the top and big in the bottom of slope linging, but smooth in the bottom of cannal, Frost-heave horizontal forces is almost zero in the bottom of cannal. That of similar trapezoidal canal is same with that of trapezoidal canal;Fifthly,the main deformation of similar trapezoidal canal is that the concrete lining lifting with the soil body, the same to trapezoidal canal, but trapezoidal canal swells the uneven modulus of deformation evidently is comparatively big, especially scalariform channel canal bottom; similar trapezoidal canal is comparatively small by the force ,the maxima stress value is 15.3 MPa, but that of trapezoidal canal can reach to 61.5 Mpa, this proves, with the same dimension , parameter of material, similar trapezoidal canal is better than trapezoidal canal in resisting to freezing.更多还原