考虑冻拨影响的寒区渠道衬砌冻胀破坏力学模型分析  

Mechanical model analysis of lining frost-heave failure in cold region considering frost-jacking

作　　者：李瀚翔 王正中[1,2] 陆立国 刘铨鸿[1,2] 江浩源 薛博祥 LI Hanxiang;WANG Zhengzhong;LU Liguo;LIU Quanhong;JIANG Haoyuan;XUE Boxiang(College of Water Resources and Architectural Engineering,Northwest A&F University,Yangling 712100,China;Cold and Arid Regions Water Engineering Safety Research Center,Northwest A&F University,Yangling 712100,China;Ningxia Water Conservancy Research Institute,Yinchuan 750021,China;State Key Laboratory of Frozen Soil Engineering,CAS,Lanzhou 730000,China)

机构地区：[1]西北农林科技大学水利与建筑工程学院,杨凌712100 [2]西北农林科技大学旱区寒区水工程安全研究中心,杨凌712100 [3]宁夏水利科学研究院,银川750021 [4]中国科学院西北生态环境资源研究院冻土工程国家重点实验室,兰州730000

出　　处：《农业工程学报》2024年第16期103-112,共10页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金项目(U2003108,51279168);国家重点研发计划“水资源高效开发利用”重点专项(2017YFC0405103);冻土工程国家重点实验室开放基金资助项目(SKLFSE201801)。

摘　　要：地下水浅埋或窄深式衬砌渠道,渠顶竖向冻胀对渠道低温稳定性影响较大,容易产生衬砌断裂、整体上抬冻害,而现有渠道冻胀工程力学模型仅分析渠坡法向冻胀。该研究考虑了渠顶竖向冻胀引起的冻拔与渠坡法向冻胀共同作用,建立了考虑冻拔的渠道冻胀工程力学模型。以冻胀敏感土质为例,应用渠道水–热–力三场耦合数值模拟,研究不同渠坡倾角、不同宽深比、不同地下水位条件下冻胀情况,以探明渠道衬砌冻拔机理,明确冻拔产生时竖向与法向冻胀分布规律。提出了冻拔破坏发生的临界坡长、临界地下水位、冻拔危险位置计算方法,同时给出了冻拔状态下渠道衬砌板内力、渠坡抗冻拔强度等计算方法。结果表明:衬砌冻拔最大拉应力与冻深和渠坡倾角正相关,与地下水位负相关。经数值模型验证,最大拉应力误差为1.5%,冻拔位置误差在16.01%以内。宁夏灌区土质条件下,冻结线半径函数斜率范围为1.047~4.040。模型解释了小型渠道易整体冻拔上抬及宽浅式渠道抗冻拔优越的原因,可以对渠道衬砌抗冻胀结构进行定量分析,为工程设计、规范修订提供参考。Shallow groundwater or narrow-deep lined canals have suffered the vertical frost heave at the top of the canal in cold regions.The lining fracture and whole uplift frost damage are also prone to occur,leading to the low stability of the canal at low temperature.However,the existing engineering models of canal frost heave have focused only on the normal one of the canal slope.This study aims to consider the combined effect of vertical frost heave on the top of the canal and normal frost heave on the slope.A mechanical engineering model was established to consider the canal frost heave.Sensitive soil was selected to simulate the moisture-heat-mechanical coupling numerical models in the canal.The frost heave was then used under different dip angles of the slope,width-to-depth ratios,and groundwater levels.The maximum tensile stress was calculated to locate the different freezing depths and dip angles of the slope during frost-jacking.The specific mechanism of canal lining was then explored to clarify the distribution of vertical and normal frost heave during frost-jacking.The internal force of canal lining plate and frost-jacking strength of canal slope were evaluated to calculate the critical slope length,critical groundwater level,and dangerous location of frost-jacking failure.Finally,the engineering mechanics model was proposed to test the actual case.The experimental data was in agreement with the field observation.The results show that the freezing counterforce was failed to offset the upper tangential frost-jacking force,particularly for the lower lining with the short slope length.The lining was also suffered from the jacking disease as a whole.Otherwise,a frost-jacking force was formed inside the lining.The greater the freezing depth and the dip angles of the slope were,the larger the area of the lining bearing the upward tangential force was,and the greater the frost-jacking tensile stress was.The position of the maximum tensile stress caused by jacking was shifted to the lower part of the canal with the i

关 键 词：渠基冻胀 冻拔 力学模型 冻胀破坏 临界坡长 

分 类 号：TV672[水利工程—水利水电工程]