動(dòng)荷載條件下凍土融化固結(jié)與變形研究
發(fā)布時(shí)間：2019-05-09 04:22
【摘要】：目前,國(guó)內(nèi)外學(xué)者針對(duì)高溫凍土融沉機(jī)理及其融沉性狀等方面做了大量研究工作,但這些研究主要集中在靜荷載作用下土體的融沉特性,很少涉及到動(dòng)荷載對(duì)水分遷移、凍脹融沉翻漿的作用,尤其是沒有考慮孔隙水壓力的變化對(duì)路基土體沉降的影響。但是對(duì)于實(shí)際工程,車輛動(dòng)荷載才能較真實(shí)地反映外界荷載狀況,孔隙水壓力的消散以及融化過程中水分的遷移和變化正是解釋融沉現(xiàn)象實(shí)質(zhì)的關(guān)鍵,對(duì)保證道路安全運(yùn)營(yíng)具有重要意義。 本文以國(guó)家自然基金課題“高溫凍土動(dòng)力融化固結(jié)理論研究”為依托,以109國(guó)道青海省境內(nèi)橡皮山段公路路基上嚴(yán)重翻漿地段為重點(diǎn),采用現(xiàn)場(chǎng)調(diào)研和實(shí)測(cè)、理論分析、及數(shù)值模擬和室內(nèi)試驗(yàn)驗(yàn)證相結(jié)合的思路,對(duì)于高溫凍土動(dòng)力融化固結(jié)特性進(jìn)行系統(tǒng)研究,從而進(jìn)一步完善凍土動(dòng)力學(xué)的學(xué)科體系。取得了以下幾個(gè)方面的研究成果： (1)針對(duì)超載及凍土性質(zhì)引起的路基凍脹翻漿問題,通過現(xiàn)場(chǎng)實(shí)測(cè),對(duì)G109在重型交通車輛作用下,不同深度、不同載重、不同車速的路基動(dòng)態(tài)響應(yīng)規(guī)律進(jìn)行了研究,并對(duì)G109沿線的路基動(dòng)態(tài)響應(yīng)狀態(tài)數(shù)據(jù)進(jìn)行了長(zhǎng)期的觀測(cè)。 (2)考慮不同冷卻溫度和融化溫度時(shí)土體分別在自重荷載和動(dòng)荷載的作用下,對(duì)109國(guó)道路基代表性土進(jìn)行飽和狀態(tài)下的融化固結(jié)作用研究,研究其在開敞系統(tǒng)有側(cè)限、不同溫度和荷載邊界條件作用下土體孔隙水壓力的變化規(guī)律。 (3)對(duì)飽和凍土在軸對(duì)稱條件下的三維融化固結(jié)理論進(jìn)行了推導(dǎo),以圓柱體試件為研究對(duì)象,推導(dǎo)出按位移求解空間間間軸對(duì)稱問題時(shí)的基本微分方程。從三場(chǎng)的基本方程出發(fā),結(jié)合凍土融化固結(jié)過程中的孔隙冰壓力和孔隙水壓力的轉(zhuǎn)化規(guī)律,導(dǎo)出飽和凍土融化固結(jié)理論模型。 (4)考慮孔隙氣壓力的作用,修訂有效應(yīng)力的表達(dá)式,考慮滲透系數(shù)為孔隙水壓力和孔隙氣壓力的函數(shù),結(jié)合土體顆粒、水、冰和氣體的質(zhì)量守恒方程以及動(dòng)量守恒方程,依據(jù)達(dá)西定律來表達(dá)氣體和水的平均運(yùn)動(dòng)速度,推導(dǎo)出非飽和高溫凍土融化固結(jié)理論模型。 (5)利用數(shù)值模擬方法,深入研究車輛動(dòng)荷載作用下凍土路基的融化固結(jié),分別建立室內(nèi)試驗(yàn)驗(yàn)證模型和季節(jié)性凍土地區(qū)109國(guó)道橡皮山段凍土路基有限元模型,綜合分析了不同邊界條件下高溫凍土融化固結(jié)沉降。圖59幅,表11個(gè),參考文獻(xiàn)131篇。
[Abstract]:At present, scholars at home and abroad have done a lot of research on the thawing mechanism of high-temperature frozen soil and its melting state, but these researches mainly focus on the melting and sinking characteristics of soil under static load, and rarely involve the dynamic load to water transfer. The effect of frost heave and thaw grouting, especially the influence of pore water pressure on the settlement of subgrade soil is not considered. But for the actual engineering, the vehicle dynamic load can reflect the external load condition more realistically, the dissipation of pore water pressure and the movement and change of water in the melting process are the key to explain the essence of the melting and sinking phenomenon. It is of great significance to ensure the safe operation of the road. Based on the National Nature Fund project "theoretical study on dynamic melting consolidation of High temperature Frozen soil", this paper focuses on the seriously overturned section of highway roadbed in the rubber mountain section of National Highway 109 in Qinghai Province, and adopts field investigation and measurement, theoretical analysis, and so on. With the combination of numerical simulation and laboratory test, the dynamic melting and consolidation characteristics of high temperature permafrost are systematically studied, so as to further improve the discipline system of frozen soil dynamics. The research results are as follows: (1) aiming at the problem of frost heave and grouting of subgrade caused by overload and frozen soil properties, through field measurement, the G109 under the action of heavy traffic vehicles, different depth, different load, The dynamic response law of roadbed with different speed is studied, and the data of subgrade dynamic response along G109 are observed for a long time. (2) considering the different cooling temperature and melting temperature, the melting and consolidation of 109 national highway subgrade representative soil under saturated state is studied under the action of self-weight load and dynamic load, respectively, and the lateral limit of the soil in the open system is studied. Variation of pore water pressure of soil under different temperature and load boundary conditions. (3) the three-dimensional thawing consolidation theory of saturated frozen soil under axisymmetric condition is derived. The basic differential equation for solving the spatial axisymmetric problem according to displacement is derived by taking the cylinder specimen as the research object. Based on the basic equations of three fields, combined with the transformation of pore ice pressure and pore water pressure during thawing and consolidation of frozen soil, a theoretical model of thawing and consolidation of saturated permafrost is derived. (4) considering the effect of pore gas pressure, the expression of effective stress is revised, and the permeability coefficient is considered as a function of pore water pressure and pore gas pressure, combined with the mass conservation equation of soil particles, water, ice and gas, as well as the momentum conservation equation. According to Darcy's law, the average velocity of gas and water is expressed, and the theoretical model of thawing consolidation of unsaturated high temperature permafrost is derived. (5) the melting consolidation of frozen soil roadbed under vehicle dynamic load is deeply studied by numerical simulation method, and the laboratory test verification model and the finite element model of permafrost roadbed of 109 National Highway in seasonal frozen soil area are established respectively. The melting and consolidation settlement of high temperature frozen soil under different boundary conditions is comprehensively analyzed. Figure 59, table 11, 131 references.
【學(xué)位授予單位】：北京交通大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2014
【分類號(hào)】：U416.16
本文編號(hào)：2472470
[Abstract]:At present, scholars at home and abroad have done a lot of research on the thawing mechanism of high-temperature frozen soil and its melting state, but these researches mainly focus on the melting and sinking characteristics of soil under static load, and rarely involve the dynamic load to water transfer. The effect of frost heave and thaw grouting, especially the influence of pore water pressure on the settlement of subgrade soil is not considered. But for the actual engineering, the vehicle dynamic load can reflect the external load condition more realistically, the dissipation of pore water pressure and the movement and change of water in the melting process are the key to explain the essence of the melting and sinking phenomenon. It is of great significance to ensure the safe operation of the road. Based on the National Nature Fund project "theoretical study on dynamic melting consolidation of High temperature Frozen soil", this paper focuses on the seriously overturned section of highway roadbed in the rubber mountain section of National Highway 109 in Qinghai Province, and adopts field investigation and measurement, theoretical analysis, and so on. With the combination of numerical simulation and laboratory test, the dynamic melting and consolidation characteristics of high temperature permafrost are systematically studied, so as to further improve the discipline system of frozen soil dynamics. The research results are as follows: (1) aiming at the problem of frost heave and grouting of subgrade caused by overload and frozen soil properties, through field measurement, the G109 under the action of heavy traffic vehicles, different depth, different load, The dynamic response law of roadbed with different speed is studied, and the data of subgrade dynamic response along G109 are observed for a long time. (2) considering the different cooling temperature and melting temperature, the melting and consolidation of 109 national highway subgrade representative soil under saturated state is studied under the action of self-weight load and dynamic load, respectively, and the lateral limit of the soil in the open system is studied. Variation of pore water pressure of soil under different temperature and load boundary conditions. (3) the three-dimensional thawing consolidation theory of saturated frozen soil under axisymmetric condition is derived. The basic differential equation for solving the spatial axisymmetric problem according to displacement is derived by taking the cylinder specimen as the research object. Based on the basic equations of three fields, combined with the transformation of pore ice pressure and pore water pressure during thawing and consolidation of frozen soil, a theoretical model of thawing and consolidation of saturated permafrost is derived. (4) considering the effect of pore gas pressure, the expression of effective stress is revised, and the permeability coefficient is considered as a function of pore water pressure and pore gas pressure, combined with the mass conservation equation of soil particles, water, ice and gas, as well as the momentum conservation equation. According to Darcy's law, the average velocity of gas and water is expressed, and the theoretical model of thawing consolidation of unsaturated high temperature permafrost is derived. (5) the melting consolidation of frozen soil roadbed under vehicle dynamic load is deeply studied by numerical simulation method, and the laboratory test verification model and the finite element model of permafrost roadbed of 109 National Highway in seasonal frozen soil area are established respectively. The melting and consolidation settlement of high temperature frozen soil under different boundary conditions is comprehensively analyzed. Figure 59, table 11, 131 references.
【學(xué)位授予單位】：北京交通大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2014
【分類號(hào)】：U416.16
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，本文編號(hào)：2472470
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