U型混凝土渠道衬砌板及横缝冻胀破坏数值模拟研究
发布时间：2018-09-03 07:45
【摘要】：本文针对北方广大季节性冻土灌区的装配式U型混凝土渠道衬砌受冻胀破坏的问题,立足宁夏银北灌区五段混凝土衬砌渠道和宁夏大学文萃校区装配式U型混凝土渠衬砌渠道冻胀观测试验区,采用调查研究、现场观测和计算机数值模拟方法,对U型混凝土渠道衬砌板及横缝冻胀破坏数值模拟进行了较为系统的研究,为装配式U型混凝土渠道防渗抗冻技术推广提供了理论依据。本文主要研究成果如下:(1)通过混凝土衬砌渠道田间冻胀试验观测分析得出:2015年12月下旬至次年1月下旬为渠基土低温期与冻胀量高值区间,温度最小值与冻胀量峰值往往出现在这一区间。渠基土温度与冻胀力、冻胀量关系密切,随着温度的降低,冻胀力、冻胀量均有升高的趋势。阳坡直线段处、阳坡弧线段处、阴坡直线段处、阳坡弧线段处四处受冻胀影响程度明显不同,其中阴坡弧段渠基土冻胀量最大。(2)通过银北灌区U型混凝土衬砌渠道实地测量分析,确定了渠道衬砌有限元模型几何参数:衬砌板的宽度为40cm、倾角为22度、厚度为6cm,横缝的宽度设定在3-18cm的取值范围,混凝土强度为C15-C30。通过裂缝观测分析得出:冻胀裂缝出现位置一般在弧线段与直线段的交界处,宽度在2mm左右,且横缝比衬砌板的冻胀破坏情况严重,阴坡衬砌板比阳坡衬砌板的破坏情况严重。(3)通过U型混凝土衬砌渠道冻胀数值模拟分析得出:横缝混凝土强度增加,有利于渠道抵抗冻胀,尤其在两段直线段表现的较为明显,而在横缝的两段弧线段的差异性并不大。通过不同混凝土强度最大冻胀位移减小量的比较,选用强度级别为C25的混凝土作为横缝材性比较适宜;在横缝宽度不断增加的过程中,横缝冻胀位移在不断减少,当横缝宽度为15cm时,阴坡最大冻胀位移减小量最大,可以作为渠道设计时横缝宽度的参考值。U型混凝土渠道的冻胀破坏主要出现在直线段与弧线段衔接处,阴坡冻胀破坏情况比阳坡更为严重,横缝比衬砌板更容易受到冻胀破坏的影响,数值模拟裂缝特征与实际冻胀裂缝观测结果基本相吻合。
[Abstract]:This paper aims at the problem of frost heaving damage to the prefabricated U-type concrete channel lining in the vast seasonal frozen soil irrigated area in the north of China. Based on the experimental area of frost heave observation of five-section concrete lining channel in Yinbei Irrigation District of Ningxia University and the assembled U-type concrete canal lining channel in Wenzi Campus of Ningxia University, the methods of investigation, field observation and computer numerical simulation are adopted. The numerical simulation of frost heaving failure of U type concrete channel lining slabs and transverse joints is studied systematically, which provides a theoretical basis for the popularization of prefabricated U type concrete channel anti-seepage and anti-freezing technology. The main research results of this paper are as follows: (1) through the observation and analysis of the field frost heave test of concrete lining channel, it is concluded that the period from late December 2015 to late January of next year is the period of low temperature and the high value of frost heave. The minimum temperature and the peak value of frost heave often appear in this range. The temperature of the base soil is closely related to the frost heave force and the frost heave quantity, and with the decrease of the temperature, the frost heave force and the frost heave volume are all increasing. The influence of frost heaving on sunny slope, sunny slope arc line, shade slope straight line and sunny slope arc is obviously different. Among them, the frost heave of the base soil in the arc section of the overcast slope is the largest. (2) through the field measurement and analysis of the U-type concrete lining channel in Yinbei Irrigation District, the geometric parameters of the finite element model of the channel lining are determined: the width of the lining plate is 40 cm, the inclination angle is 22 degrees, The thickness is 6 cm, the width of transverse joint is set in the range of 3-18cm, and the strength of concrete is C15-C30. Through the observation and analysis of cracks, it is concluded that the position of frost heaving crack is generally at the junction of arc section and straight line section, the width is about 2mm, and the transverse joint is more serious than the frost heaving damage of lining plate. (3) through numerical simulation analysis of frost heave of U type concrete lining channel, it is concluded that the strength of transverse joint concrete is increased, which is helpful to resist frost heave, especially in two straight sections. However, the difference between the two arcs in the transverse seam is not great. Through the comparison of the maximum frost heaving displacement of different concrete strength, the concrete with strength grade C25 is suitable for the transverse joint, and the frost heave displacement of the transverse joint decreases continuously with the increasing of the width of the transverse joint. When the width of transverse joint is 15cm, the maximum frost heave displacement of shady slope decreases the most, which can be used as the reference value of transverse joint width. The frost heave damage of shady slope is more serious than that of sunny slope, and the transverse joint is more easily affected by frost heave failure than the lining slab, and the numerical simulation crack characteristics are basically consistent with the observed results of the actual frost heave crack.
【学位授予单位】：宁夏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV544;TV698.2
[Abstract]:This paper aims at the problem of frost heaving damage to the prefabricated U-type concrete channel lining in the vast seasonal frozen soil irrigated area in the north of China. Based on the experimental area of frost heave observation of five-section concrete lining channel in Yinbei Irrigation District of Ningxia University and the assembled U-type concrete canal lining channel in Wenzi Campus of Ningxia University, the methods of investigation, field observation and computer numerical simulation are adopted. The numerical simulation of frost heaving failure of U type concrete channel lining slabs and transverse joints is studied systematically, which provides a theoretical basis for the popularization of prefabricated U type concrete channel anti-seepage and anti-freezing technology. The main research results of this paper are as follows: (1) through the observation and analysis of the field frost heave test of concrete lining channel, it is concluded that the period from late December 2015 to late January of next year is the period of low temperature and the high value of frost heave. The minimum temperature and the peak value of frost heave often appear in this range. The temperature of the base soil is closely related to the frost heave force and the frost heave quantity, and with the decrease of the temperature, the frost heave force and the frost heave volume are all increasing. The influence of frost heaving on sunny slope, sunny slope arc line, shade slope straight line and sunny slope arc is obviously different. Among them, the frost heave of the base soil in the arc section of the overcast slope is the largest. (2) through the field measurement and analysis of the U-type concrete lining channel in Yinbei Irrigation District, the geometric parameters of the finite element model of the channel lining are determined: the width of the lining plate is 40 cm, the inclination angle is 22 degrees, The thickness is 6 cm, the width of transverse joint is set in the range of 3-18cm, and the strength of concrete is C15-C30. Through the observation and analysis of cracks, it is concluded that the position of frost heaving crack is generally at the junction of arc section and straight line section, the width is about 2mm, and the transverse joint is more serious than the frost heaving damage of lining plate. (3) through numerical simulation analysis of frost heave of U type concrete lining channel, it is concluded that the strength of transverse joint concrete is increased, which is helpful to resist frost heave, especially in two straight sections. However, the difference between the two arcs in the transverse seam is not great. Through the comparison of the maximum frost heaving displacement of different concrete strength, the concrete with strength grade C25 is suitable for the transverse joint, and the frost heave displacement of the transverse joint decreases continuously with the increasing of the width of the transverse joint. When the width of transverse joint is 15cm, the maximum frost heave displacement of shady slope decreases the most, which can be used as the reference value of transverse joint width. The frost heave damage of shady slope is more serious than that of sunny slope, and the transverse joint is more easily affected by frost heave failure than the lining slab, and the numerical simulation crack characteristics are basically consistent with the observed results of the actual frost heave crack.
【学位授予单位】：宁夏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV544;TV698.2
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