冻胀反力系数在渠道衬砌冻胀弹性地基梁模型中的应用  

Application of reaction force coefficient in the mechanical model for the elastic foundation beam of canal lining during frost heave

作　　者：李宗利 姚希望[3] 李云波 吴正桥 肖帅鹏[2] 刘士达 Li Zongli;Yao Xiwang;Li Yunbo;Wu Zhengqiao;Xiao Shuaipeng;Liu Shida(Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas of Ministry of Education,Northwest A&F University,Yangling 712100,China;College of Water Resources and Architectural Engineering,Northwest A&F University,Yangling 712100,China;China Water Resources Bei Fang Investigation Design&Research Co.Ltd.,Tianjin 300222,China)

机构地区：[1]西北农林科技大学旱区农业水土工程教育部重点实验室,杨凌712100 [2]西北农林科技大学水利与建筑工程学院,杨凌712100 [3]中水北方勘测设计研究有限责任公司,天津300222

出　　处：《农业工程学报》2021年第17期97-106,共10页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家重点研发计划(2017YFC0405101)。

摘　　要：为了探究渠道基土在冻胀过程中的非线性变形特性对渠道衬砌冻胀的影响,基于冻土三轴试验结果,建立考虑围压和温度的邓肯-张本构模型,参考室内三轴试验测定基床系数方法,应用数值模拟法建立冻胀反力系数随被约束冻胀量变化的计算式,并基于有限差分法离散弹性地基梁平衡微分方程。模型考虑衬砌不同点因被约束冻胀量不同引起冻胀反力系数不同的取值问题,克服以往模型中冻胀反力系数取常量的不足。应用解析解验证模型的合理性,探究冻胀反力系数分别为变量与常量时在梯形渠道衬砌冻胀力学响应计算结果上的差异。结果表明,对于边坡和渠底衬砌板,常量冻胀反力系数计算出的最大冻胀反力是变量的1.43倍,计算出的弯矩最大值平均是变量的1.12倍。因此在采用弹性地基梁理论分析渠道衬砌冻胀问题时,若冻胀反力系数采用常量,不考虑冻土的非线性变形,会使得计算结果偏大。研究结果可为大型梯形渠道衬砌抗冻胀设计提供参考。Canal foundation soil is generally characterized by nonlinear deformation during the frost heaving process.In this study,a Duncan-Chang constitutive model was established considering the confining pressure and temperature,according to the frozen soil triaxial test.A numerical simulation was conducted to establish the calculation formula for the frost heave reaction force coefficient with the constrained frost heave change,particularly referring to the bed coefficient in the indoor triaxial test.The balance differential equation of the elastic foundation beam was discretized to adapt to the change of frost heave reaction coefficient using the finite difference method.Since the frost heave reaction coefficient greatly varied at different points of lining,the model increased significantly the much more constants than before.Analytical solutions were also applied to verify the new model.In addition,the difference was also determined,when the frost heave reaction force coefficients were variable and constant,particularly for the frost heave mechanical response of trapezoidal canal lining.The results showed that the frost heave reaction force increased by 0.15 MPa on average,while the frost heave reaction force coefficient decreased by 1.12 MPa/m on average at the same freezing temperature for every 1 cm increase in the constrained frost heave.The frost heave reaction force increased by 0.21 times on average for every 5°C decrease at freezing temperature under the same restricted frost heave amount.As such,the hyperbolic function was used to represent this change suitable for engineering applications.In slope and canal bottom lining slabs,the maximum frost heave reaction force calculated by the constant frost heave reaction force coefficient was 1.43 times the variable,and the maximum bending moment was 1.12 times the variable on average.Therefore,the nonlinear deformation of frozen soil was not considered to avoid a larger value than before,if the frost heave reaction coefficient was constant.Moreover,the significant

关 键 词：渠道 冻土 冻胀反力系数 非线性变形 弹性地基梁 力学模型 

分 类 号：TU445[建筑科学—岩土工程] TV91[建筑科学—土工工程]