【摘要】：近年來,隨著核廢料填埋、地源熱泵、垃圾填埋、熱排水固結(jié)軟基處理等工程技術(shù)的興起,以及大型災(zāi)難性爆炸事故產(chǎn)生的高溫、高熱爆炸產(chǎn)物在巖土體中的傳播、擴散及其對地下建構(gòu)筑物的損傷破壞,使得巖土體中熱流固(THM)耦合問題引起廣泛的關(guān)注,相應(yīng)的研究也得以迅速發(fā)展。由于巖土體熱流固耦合效應(yīng)涉及滲流力學(xué)、土(動)力學(xué)、傳熱學(xué)等多個學(xué)科,影響因素多而復(fù)雜,現(xiàn)有研究難以全面、系統(tǒng)地揭示巖土體中熱流固耦合作用機理。為此,本文從理論、實驗與計算模擬三方面出發(fā)對飽和軟土在溫度影響下的特性變化從固結(jié)到動力進行了研究,主要研究內(nèi)容如下：(1)從Biot固結(jié)理論與傅里葉傳熱理論出發(fā),推導(dǎo)建立了多孔介質(zhì)熱彈性非線性耦合固結(jié)方程,并將其退化求解了無限空間中無限長柱形孔洞與有限長圓柱形熱源熱固結(jié)問題,以及各向等壓下不排水加熱飽和土樣熱響應(yīng)問題。在此基礎(chǔ)上,分析了各耦合項(水土壓縮項、固液相熱沉等)與非線性項(熱對流)對計算結(jié)果的影響。(2)在多孔介質(zhì)熱彈性理論基礎(chǔ)上,針對各向等壓不排水和排水加熱情況,采用彈性、非線性彈性、考慮溫度影響的修正劍橋模型,結(jié)合溫度對水的熱膨脹系數(shù)的影響,采用COMSOL有限元軟件對三軸試樣熱固結(jié)問題進行了求解。同時開展了相應(yīng)的溫控三軸試驗,將解析、數(shù)值計算結(jié)果與試驗結(jié)果進行了對比分析,討論了泊松比、彈性模量、水的體膨脹系數(shù)等參數(shù)對結(jié)果的影響。利用COMSOL有限元軟件,研究熱固結(jié)技術(shù)在豎井地基加固中的作用機理。在此基礎(chǔ)上,建立了熱固結(jié)本構(gòu)關(guān)系并自主開發(fā)了相應(yīng)的豎井熱固結(jié)有限元程序TSDSS,彌補了THM耦合理論中采用不考慮溫度影響的本構(gòu)關(guān)系無法計算加溫排水豎井地基沉降量增大問題,進而通過相應(yīng)的模型實驗,對程序與本構(gòu)關(guān)系進行了驗證。(3)對寧波軟粘土開展了先固結(jié)后不排水加溫、先排水加熱固結(jié)后剪切、先固結(jié)再剪切到一定程度變形然后不排水加熱、先排水加熱固結(jié)后不排水動力循環(huán)試驗四類溫控三軸試驗,并對試驗現(xiàn)象進行了分析,研究了溫度對軟土的抗剪強度、孔壓與變形的影響。其次,在THM耦合理論的基礎(chǔ)上,引入考慮溫度影響的修正劍橋模型和邊界面模型,并在ABAQUS中實現(xiàn)相應(yīng)的有限元計算方法,對開展的溫控三軸試驗進行了模擬。(4)基于廣義熱彈性理論及Biot動力方程,建立了飽和多孔介質(zhì)熱流固耦合動力響應(yīng)(THMD)控制方程,首先對無限土柱的熱動力響應(yīng)問題進行了求解,并探討了各因素變化對結(jié)果的影響。其次,在COMSOL中建立了無限空間柱形孔洞模型,研究了熱流固耦合動力響應(yīng)(THMD)控制方程中非線性項對計算結(jié)果的影響。最后,利用所建立的THMD控制方程,研究了熱流固耦合波動問題,探討各因素對P1波、P2波、T波傳播的影響。
[Abstract]:In recent years, with the rise of engineering technologies such as nuclear waste landfill, ground source heat pump, refuse landfill, thermal drainage and consolidation of soft foundation treatment, as well as the high temperature caused by large-scale catastrophic explosion and the propagation of high heat explosion products in rock and soil, Diffusion and its damage to underground structures cause extensive attention to the problem of heat-fluid-solid (THM) coupling in rock and soil, and the corresponding research has been developed rapidly. Because the heat-fluid-solid coupling effect of rock and soil mass involves many disciplines such as seepage mechanics, soil (dynamic) mechanics, heat transfer and so on, the influence factors are many and complex, and the existing research is difficult to reveal systematically the mechanism of heat-fluid-solid coupling in rock and soil mass. Therefore, in this paper, the characteristics of saturated soft soil under the influence of temperature are studied from three aspects: theoretical, experimental and computational simulation, from consolidation to dynamic. The main contents are as follows: (1) based on the Biot consolidation theory and Fourier heat transfer theory, the nonlinear coupled consolidation equations of thermal elasticity in porous media are derived and established. The thermal consolidation problems of infinite cylindrical voids and finite cylindrical heat sources in infinite space and the thermal response of undrained saturated soil samples under isotropic pressure are also solved. On this basis, the effects of coupling terms (soil and water compression term, solid-liquid phase heat sink, etc.) and non-linear term (thermal convection) on the calculation results are analyzed. (2) on the basis of the thermal elasticity theory of porous media, the influence of the coupling terms on the calculation results is analyzed. The modified Cambridge model, which is elastic and nonlinear, considering the effect of temperature on the coefficient of thermal expansion of water, is adopted to solve the problem of non-drainage and drainage heating under isotropic pressure, and the influence of temperature on the coefficient of thermal expansion of water is considered. The COMSOL finite element software was used to solve the thermal consolidation problem of triaxial specimens. At the same time, the corresponding temperature controlled triaxial test was carried out. The analytical and numerical results were compared with the experimental results. The effects of Poisson's ratio, elastic modulus and water expansion coefficient on the results were discussed. By using COMSOL finite element software, the mechanism of thermal consolidation technology in the consolidation of shaft foundation is studied. On the basis of this, the constitutive relation of thermal consolidation is established and the corresponding finite element program TSDSS, for shaft thermal consolidation is developed. It makes up for the problem that it is impossible to calculate the settlement of heated drainage shaft foundation by using the constitutive relation which does not consider the effect of temperature in THM coupling theory, and then through the corresponding model experiment, The program and constitutive relation are verified. (3) the Ningbo soft clay is solidified first and then heated without drainage, then heated and consolidated by drainage and then shear, then deformed to a certain extent and then heated without drainage. Four kinds of temperature controlled triaxial tests were carried out in heating consolidation and undrained dynamic cycle tests, and the effects of temperature on shear strength, pore pressure and deformation of soft soil were studied in this paper, and the effects of temperature on shear strength, pore pressure and deformation of soft soil were studied. Secondly, on the basis of THM coupling theory, the modified Cambridge model and boundary interface model considering temperature effect are introduced, and the corresponding finite element method is implemented in ABAQUS. The temperature-controlled triaxial test was simulated. (4) based on the generalized thermoelasticity theory and Biot dynamic equation, the (THMD) governing equation of thermal-fluid-solid coupling dynamic response for saturated porous media was established. Firstly, the thermal dynamic response of infinite soil columns is solved, and the influence of various factors on the results is discussed. Secondly, the cylindrical cavity model in infinite space is established in COMSOL, and the influence of the nonlinear term in the (THMD) governing equation of heat-fluid-solid coupling dynamic response on the calculated results is studied. Finally, the heat-fluid-solid coupling wave problem is studied by using the established THMD governing equation, and the effects of various factors on the P _ 1 wave, P _ 2 wave and T-wave propagation are discussed.
【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2015
【分類號】：TU447

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本文編號：2460619