摘要
南水北调中线工程在冰期输水过程中将会出现冰盖温度膨胀力,尤其可能影响渡槽结构的安全。但是冰的力学特性非常复杂,影响因素很多,同时渡槽结构纵向尺度与冰盖厚度相差悬殊,因此采取如下研究思路:首先在室内对小尺度冰试件进行多条件的膨胀力测试,而后建立小尺度试件的有限元仿真数学模型,并根据试验测试结果对数学模型进行调试验证,最后利用校核后的数学模型对渡槽结构的冰盖膨胀力进行分析计算。研究发现:冰温度膨胀力极值随冰厚的增长呈现出近似于线性增长的变化趋势;冰盖厚度不同,温度膨胀力也呈现出不同的变化特征:冰盖厚度越大,温度膨胀力增长速度越快,膨胀力极值越大,到达极值后,膨胀力下降速度越慢;渡槽内,将冰的温度膨胀力作为线载荷考虑时,可达102.21kN/m,这一量级的水平载荷作用,将对渡槽结构的安全性造成威胁。南水北调中线工程冰期输水过程中应采取措施,避免渡槽结构内形成稳定冰盖。
The ice thermal expansive pressure occurs in the water diversion of the Middle Route of the South-to-North Water Diversion Project during the ice period, which may affect the safety of the aqueduct structure. However, the mechanical properties of ice are complex and have numerous influencing factors, and the vertical scale of the aqueduct structure is very different from the ice thickness. In this paper, the laboratory expansive pressure tests were conducted for the small scale ice samples under different conditions and the finite element numerical model was then developed for the small scale ice samples. The numerical mod- el was calibrated based on the laboratory test results, and then the calibrated numerical model was used to analyze the ice thermal expansive pressure acting on the aqueduct structure. The results showed that （1） There is a linear relationship between the extreme value of the ice thermal expansive pressure and ice thickness; （2） The ice thermal expansive pressure varies with the ice thickness. With the increasing of the ice thickness, the ice thermal pressure has a high growth rate and a high extreme value. When the ice thermal pressure reaches the extreme value, it has a lower decreasing rate;（3） The maximum value of the thermal expansive pressure acting on the aqueduct structure can be 102.21 kN/m,which poses a threat for the safety of the aqueduct structure. Therefore, for the water diversion of the Middle Route of the South-to-North Water Diversion Project during the ice period,appropriate measures should be conducted to avoid the occurrence of stable ice in the aqueduct structure.
出处
《南水北调与水利科技》
CAS
CSCD
北大核心
2012年第3期7-11,共5页
South-to-North Water Transfers and Water Science & Technology
基金
国家重大科技专项(2012ZX07205005)
教育部"长江学者和创新团队发展计划"创新团队(IRT0851)
国家创新研究群体科学基金(51021004)
关键词
冰期输水
渡槽
温度膨胀力
室内模型试验
有限元模型
water diversion during the Ice period
aqueduct
thermal expansive pressure
laboratory experiment
finite elementmodel
