寒区渠道工程冻融灾变链式模型及断链减灾研究
发布时间：2018-12-19 08:44
【摘要】：渠道冻胀破坏是冻土地区存在的主要灾害形式之一,我国大部分地区处于纬度较高地带,国土面积的75%为永久冻土区与季节性冻土区。随着季节变换,昼夜更替,在正负温差作用下,岩土产生冻胀和融沉,而在这两种作用下,岩土内部结构由此发生改变,从而影响其物理及力学性质,岩土产生冻胀、融沉造成的渠道工程损坏在我国北方地区频繁发生。因此,渠道冻害是寒区渠道建设亟需要解决的工程问题。本文针对渠道冻胀灾害发生形成的条件及其产生破坏的过程进行了深入的探讨,从渠道冻胀灾害形成的水分条件、土质条件和温度条件的分析入手,根据灾变链式理论的普适性原则,依据链式灾害理论,对渠道冻胀成灾机理作了细致的分析论述,说明渠道衬砌结构冻胀破坏的形成与发展具有链式规律性。论文以理论分析、原型渠道冻胀试验、数值模拟为主要研究方法,对引起渠道冻胀的因素综合分析,以期为寒区渠道工程的设计和施工提供理论和依据。本文的主要研究结论与成果如下:(1)根据灾变链式理论的普适性原则,依据链式灾害理论,分析渠道冻胀灾害形成的水分条件、土质条件和温度条件,建立了渠道冻胀破坏链式模型。(2)通过现场原型渠道试验对渠道冻胀破坏分析,观测气温、地温、土质、土壤水分、冻深、冻胀变形量、冻胀应力等因素,分析得到了渠道冻胀破坏的链式规律。试验观测表明,随着气温降低,地温持续降低,渠道各部位的渠基土含水率也因此产生变化,渠基土含水率在距地表60 cm深度范围处增大,呈聚集势态形成冻结锋面。冻结期,渠道阴坡地温最低温度为-25℃,对应最大冻深为146.2 cm冻胀应力为178 kPa;阳坡地温最低值是-21℃,对应最大冻深为123.5 cm冻胀应力为154 kPa;渠底地温最低值是-23℃,对应最大冻深为147.2 cm冻胀应力为163 kPa。(3)通过数值模拟,分析得到了渠道冻胀破坏过程中,渠基土体温度场与应力应变场的变化分布规律。随着渠基土体深度的增加温度梯度逐渐减小,温度等值线越靠近底部越接近于水平直线。模拟得到渠道不同部位的最大冻深分别为阴坡139.8 cm、渠底141.3 cm、阳坡122.4 cm,最大冻胀变形为11.89 cm,发生在渠道底部。渠道衬砌表面主应力分布集中的区域,位于渠底板中间部位和渠道阴坡的衬砌板表面以及渠坡板接近坡脚位置处。(4)研究渠道冻胀链式关系,分析现场原型试验观测数据,结合前人做过的渠道防冻胀试验结果,建立了渠道冻胀断链减灾模型,以此为依据,提出合理的渠道冻胀的防灾减灾措施。
[Abstract]:Channel frost heave damage is one of the main disaster forms in frozen soil regions. Most areas of China are located in higher latitudes and 75% of the land area is permafrost and seasonal permafrost regions. With the change of seasons, the change of day and night, under the action of positive and negative temperature difference, the rock and soil produce frost heaving and thawing, and under these two kinds of actions, the internal structure of rock and soil changes, thus affecting its physical and mechanical properties, resulting in frost heaving of rock and soil. The channel engineering damage caused by melt sinking occurs frequently in northern China. Therefore, channel freezing injury is an urgent engineering problem to be solved in channel construction in cold regions. In this paper, the formation conditions and damage process of channel frost heaving disaster are discussed, and the water condition, soil quality condition and temperature condition of channel frost heaving disaster are analyzed. According to the universal principle of catastrophe chain theory and the chain hazard theory, the mechanism of frost heave formation of canal is analyzed and discussed in detail. It is shown that the formation and development of frost heave damage of canal lining structure have chain regularity. In this paper, theoretical analysis, prototype channel frost heave test and numerical simulation are used as the main research methods to analyze comprehensively the factors causing channel frost heave, in order to provide the theory and basis for the design and construction of canal engineering in cold region. The main conclusions and achievements of this paper are as follows: (1) according to the universal principle of catastrophe chain theory and chain disaster theory, the water condition, soil quality condition and temperature condition of frost heaving disaster are analyzed. A chain model of channel frost heaving failure is established. (2) the analysis of channel frost heave failure is carried out through field prototype channel test, and the factors such as air temperature, ground temperature, soil quality, soil moisture, freezing depth, frost heave deformation, frost heave stress and so on are observed. The chain law of channel frost heaving failure is obtained. The experimental results show that with the decrease of air temperature and the continuous decrease of soil temperature, the moisture content of the canal soil in various parts of the canal also changes, and the moisture content of the canal base soil increases in the depth range of 60 cm from the surface, forming a freezing front in the aggregation state. During the freezing period, the minimum temperature of channel shady slope is -25 鈩，
本文编号：2386685
[Abstract]:Channel frost heave damage is one of the main disaster forms in frozen soil regions. Most areas of China are located in higher latitudes and 75% of the land area is permafrost and seasonal permafrost regions. With the change of seasons, the change of day and night, under the action of positive and negative temperature difference, the rock and soil produce frost heaving and thawing, and under these two kinds of actions, the internal structure of rock and soil changes, thus affecting its physical and mechanical properties, resulting in frost heaving of rock and soil. The channel engineering damage caused by melt sinking occurs frequently in northern China. Therefore, channel freezing injury is an urgent engineering problem to be solved in channel construction in cold regions. In this paper, the formation conditions and damage process of channel frost heaving disaster are discussed, and the water condition, soil quality condition and temperature condition of channel frost heaving disaster are analyzed. According to the universal principle of catastrophe chain theory and the chain hazard theory, the mechanism of frost heave formation of canal is analyzed and discussed in detail. It is shown that the formation and development of frost heave damage of canal lining structure have chain regularity. In this paper, theoretical analysis, prototype channel frost heave test and numerical simulation are used as the main research methods to analyze comprehensively the factors causing channel frost heave, in order to provide the theory and basis for the design and construction of canal engineering in cold region. The main conclusions and achievements of this paper are as follows: (1) according to the universal principle of catastrophe chain theory and chain disaster theory, the water condition, soil quality condition and temperature condition of frost heaving disaster are analyzed. A chain model of channel frost heaving failure is established. (2) the analysis of channel frost heave failure is carried out through field prototype channel test, and the factors such as air temperature, ground temperature, soil quality, soil moisture, freezing depth, frost heave deformation, frost heave stress and so on are observed. The chain law of channel frost heaving failure is obtained. The experimental results show that with the decrease of air temperature and the continuous decrease of soil temperature, the moisture content of the canal soil in various parts of the canal also changes, and the moisture content of the canal base soil increases in the depth range of 60 cm from the surface, forming a freezing front in the aggregation state. During the freezing period, the minimum temperature of channel shady slope is -25 鈩，
本文编号：2386685
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