【摘要】：渠道凍脹破壞是凍土地區(qū)存在的主要災(zāi)害形式之一,我國(guó)大部分地區(qū)處于緯度較高地帶,國(guó)土面積的75%為永久凍土區(qū)與季節(jié)性凍土區(qū)。隨著季節(jié)變換,晝夜更替,在正負(fù)溫差作用下,巖土產(chǎn)生凍脹和融沉,而在這兩種作用下,巖土內(nèi)部結(jié)構(gòu)由此發(fā)生改變,從而影響其物理及力學(xué)性質(zhì),巖土產(chǎn)生凍脹、融沉造成的渠道工程損壞在我國(guó)北方地區(qū)頻繁發(fā)生。因此,渠道凍害是寒區(qū)渠道建設(shè)亟需要解決的工程問題。本文針對(duì)渠道凍脹災(zāi)害發(fā)生形成的條件及其產(chǎn)生破壞的過程進(jìn)行了深入的探討,從渠道凍脹災(zāi)害形成的水分條件、土質(zhì)條件和溫度條件的分析入手,根據(jù)災(zāi)變鏈?zhǔn)嚼碚摰钠者m性原則,依據(jù)鏈?zhǔn)綖?zāi)害理論,對(duì)渠道凍脹成災(zāi)機(jī)理作了細(xì)致的分析論述,說明渠道襯砌結(jié)構(gòu)凍脹破壞的形成與發(fā)展具有鏈?zhǔn)揭?guī)律性。論文以理論分析、原型渠道凍脹試驗(yàn)、數(shù)值模擬為主要研究方法,對(duì)引起渠道凍脹的因素綜合分析,以期為寒區(qū)渠道工程的設(shè)計(jì)和施工提供理論和依據(jù)。本文的主要研究結(jié)論與成果如下:(1)根據(jù)災(zāi)變鏈?zhǔn)嚼碚摰钠者m性原則,依據(jù)鏈?zhǔn)綖?zāi)害理論,分析渠道凍脹災(zāi)害形成的水分條件、土質(zhì)條件和溫度條件,建立了渠道凍脹破壞鏈?zhǔn)侥Ｐ汀?2)通過現(xiàn)場(chǎng)原型渠道試驗(yàn)對(duì)渠道凍脹破壞分析,觀測(cè)氣溫、地溫、土質(zhì)、土壤水分、凍深、凍脹變形量、凍脹應(yīng)力等因素,分析得到了渠道凍脹破壞的鏈?zhǔn)揭?guī)律。試驗(yàn)觀測(cè)表明,隨著氣溫降低,地溫持續(xù)降低,渠道各部位的渠基土含水率也因此產(chǎn)生變化,渠基土含水率在距地表60 cm深度范圍處增大,呈聚集勢(shì)態(tài)形成凍結(jié)鋒面。凍結(jié)期,渠道陰坡地溫最低溫度為-25℃,對(duì)應(yīng)最大凍深為146.2 cm凍脹應(yīng)力為178 kPa;陽(yáng)坡地溫最低值是-21℃,對(duì)應(yīng)最大凍深為123.5 cm凍脹應(yīng)力為154 kPa;渠底地溫最低值是-23℃,對(duì)應(yīng)最大凍深為147.2 cm凍脹應(yīng)力為163 kPa。(3)通過數(shù)值模擬,分析得到了渠道凍脹破壞過程中,渠基土體溫度場(chǎng)與應(yīng)力應(yīng)變場(chǎng)的變化分布規(guī)律。隨著渠基土體深度的增加溫度梯度逐漸減小,溫度等值線越靠近底部越接近于水平直線。模擬得到渠道不同部位的最大凍深分別為陰坡139.8 cm、渠底141.3 cm、陽(yáng)坡122.4 cm,最大凍脹變形為11.89 cm,發(fā)生在渠道底部。渠道襯砌表面主應(yīng)力分布集中的區(qū)域,位于渠底板中間部位和渠道陰坡的襯砌板表面以及渠坡板接近坡腳位置處。(4)研究渠道凍脹鏈?zhǔn)疥P(guān)系,分析現(xiàn)場(chǎng)原型試驗(yàn)觀測(cè)數(shù)據(jù),結(jié)合前人做過的渠道防凍脹試驗(yàn)結(jié)果,建立了渠道凍脹斷鏈減災(zāi)模型,以此為依據(jù),提出合理的渠道凍脹的防災(zāi)減災(zāi)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，

本文編號(hào)：2386685