不同地下水位下渠基冻胀规律与保温板适宜厚度确定  

Law of frost heave of canal foundation and appropriate thickness of insulation board under different groundwater levels

作　　者：郭富强[1,2] 史海滨 程满金[2] 高文慧 Guo Fuqiang;Shi Haibin;Cheng Manjin;Gao Wenhui(College of Water Conservancy and Civil Engineering,Inner Mongolia Agriculture University,Hohhot 010018,China;Inner Mongolian Autonomous Region Research Institute on Hydraulic Sciences,Hohhot 010060,China)

机构地区：[1]内蒙古农业大学水利与土木建筑工程学院,呼和浩特010018 [2]内蒙古自治区水利科学研究院,呼和浩特010060

出　　处：《农业工程学报》2018年第19期95-103,共9页Transactions of the Chinese Society of Agricultural Engineering

基　　金：内蒙古自治区水利科研专项经费项目(NSK-2016-S9)

摘　　要：为探明河套灌区不同地下水位条件下渠基冻胀的差异,了解地下水位变化对渠基土壤水分迁移和力学性能的影响,该文通过建立不同地下水位冻胀试验平台并结合原型渠道,分析了不同地下水位对铺设不同厚度聚苯板的基土冻胀的影响,阐述了冻胀率和截面弯矩沿渠坡的分布规律,提出了不同地下水位下聚苯板适宜铺设厚度的理论计算公式。试验得出,每降低1 cm地下水位,基土冻胀量减小0.15 cm。当地下水位降低0.5~1.0 m后,削减冻胀率为71%~83.8%。地下水位下降有效阻止或延缓了土壤毛细水的上升,降低了0~30 cm土层的土壤水分,有效阻止了冻结锋面水分的迁移,减小了土体中冰夹层的形成,从而降低了土体的冻胀变形。并且,渠道的冻胀破坏部位随着地下水位的不同而发生变化。该研究可为北方季节性冻土区骨干渠道保温防冻胀技术研究提供科学依据和技术支撑。In order to find out the difference of canal foundation frost heave in Hetao irrigation area under different underground water levels,and to understand the influence of the changes of groundwater level on soil moisture transfer and mechanical properties of canal foundation,the test was carried out by setting up a test platform for frost heave under different underground water levels.And combined with the prototype channel,the effect of different groundwater levels on frost heave of foundation soil covered with different thickness of polystyrene board was analyzed,the distribution law of frost heave rate and section bending moment along channel slope was described,and a theoretical formula for calculating the suitable thickness of polystyrene board at different underground water levels was presented.It is found that the frost heaving of base soil decreases by 0.15 cm when the groundwater level is reduced by 1 cm.When the groundwater level is reduced by 0.5-1.0 m,the frost heave rate is reduced by 71%-83.8%.The decline of groundwater level effectively prevents or delays the increase of capillary water in soil,reduces the soil moisture of 0-30 cm soil layer,effectively prevents the migration of the water of freezing front,reduces the formation of ice interlayer in soil,and reduces the frost heaving deformation of soil.The frost heaving damage parts of the channel change with the change of the groundwater level.Through the analysis of ground temperature monitoring data,this paper puts forward the lowest temperature under the condition of laying 2-10 cm polystyrene board,fits the relation between the thickness of insulation board and the lowest temperature under the board at different underground water levels,and calculates the laying thickness of polystyrene board under different groundwater levels when the negative temperature does not exist under the board,so as to explore a relation between the suitable thickness for polystyrene board laying and groundwater depth.According to the theoretical formula,the variation

关 键 词：地下水 水位 EPS 冻胀理论 截面弯矩 水分迁移规律 

分 类 号：S143[农业科学—肥料学] S278[农业科学—农业基础科学]