表土段凍結(jié)壁解凍過程中斜井井壁受力規(guī)律研究
發(fā)布時間：2019-01-21 19:58
【摘要】：凍結(jié)法鑿井工程中,斜井井壁在凍結(jié)壁解凍過程中的受力情況,歷來是斜井建設(shè)工程的一個研究盲點。而伴隨著凍結(jié)壁解凍,斜井井壁受溫度場、水分場、力場等多場作用,受力工況復雜。開展此階段研究工作,對斜井井壁設(shè)計、施工大有裨益。基于此,本文采用數(shù)值模擬與模型試驗相結(jié)合的方法,對表土段凍結(jié)壁解凍過程中斜井井壁的受力規(guī)律進行了研究。在數(shù)值模擬計算中,首先結(jié)合試驗裝置建立了平面有限元模型,對液壓囊加載系統(tǒng)的可靠性進行了驗證計算。并在此基礎(chǔ)上,對可能影響加載系統(tǒng)的相關(guān)參數(shù)進行了單因素分析。最后,利用順序耦合的方法,對溫度場、應力場進行耦合作用分析,得到了斜井井壁在凍結(jié)壁解凍過程中的受力規(guī)律。研究表明,采用液壓囊、水壓共同加載以達到封閉空間內(nèi)三軸加載效果的試驗方案是可行的。加載過程中,加壓鋼板厚度與土體水平側(cè)壓力系數(shù)取值對加載效果的影響比較大。凍結(jié)壁在解凍過程中,井壁內(nèi)、外緣關(guān)鍵點的受力基本上都呈現(xiàn)逐漸增大的趨勢。其中,井壁頂拱內(nèi)緣中心受到的拉應力最大,仰拱內(nèi)緣中心發(fā)生的徑向位移最大,此兩點受力在井壁各關(guān)鍵點中處于最不利狀態(tài)。在井壁結(jié)構(gòu)設(shè)計、施工過程中,應予以著重考慮。在模型試驗中,首先通過數(shù)值計算,確定了鋼質(zhì)模型井壁的尺寸。并利用該模型井壁進行了靜水壓加載試驗、純地壓加載試驗、地壓與孔隙水壓聯(lián)合作用試驗以及凍結(jié)壁解凍過程中的井壁受力模擬試驗。研究發(fā)現(xiàn),靜水壓力試驗中,模型井壁兩端有無圓形鋼頭對試驗中井壁的受力影響微乎其微,實測出的井壁環(huán)向應變與數(shù)值模擬計算的結(jié)果基本上完全吻合。純地壓加載試驗中,仰拱內(nèi)緣中心的環(huán)向應變與頂拱內(nèi)緣中心的環(huán)向應變均隨著Y方向荷載Yp的增加而線性增大;Yp大小一定時,X方向荷載Xp越大,仰拱內(nèi)緣中心和頂拱內(nèi)緣中心的環(huán)向應變越小。地壓與孔隙水壓聯(lián)合作用試驗中,仰拱內(nèi)緣中心的環(huán)向應變隨著孔隙水壓的增加而增大,頂拱內(nèi)緣中心的環(huán)向應變隨著孔隙水壓的增加而減小。凍結(jié)壁解凍階段加載試驗中,模型井壁中的溫度應力抑制了頂拱內(nèi)緣中心與仰拱內(nèi)緣中心在凍結(jié)壁解凍過程中受到的孔隙水壓拉應力作用,頂拱與仰拱中心環(huán)向應變隨著凍結(jié)壁溫度的上升而逐漸減小,這與數(shù)值模擬計算得到的結(jié)果不相一致。最后,給出了通過開展數(shù)值模擬與模型試驗研究得到的主要結(jié)論,并針對研究過程中出現(xiàn)的不足提出了改善性建議。
[Abstract]:The stress of inclined shaft wall during thawing process is always a blind spot of inclined shaft construction project. With the freezing wall thawing, the inclined shaft wall is subjected to many fields, such as temperature field, moisture field, force field and so on. The research work at this stage is of great benefit to the design and construction of inclined shaft lining. Based on this, the method of numerical simulation and model test is used to study the force law of inclined shaft wall during thawing process of frozen wall in surface soil section. In the numerical simulation, the plane finite element model is established in combination with the test device, and the reliability of the hydraulic bag loading system is verified and calculated. On the basis of this, the single factor analysis of the related parameters that may affect the loading system is carried out. Finally, by using the method of sequential coupling, the coupling effect of temperature field and stress field is analyzed, and the force law of inclined shaft wall during the thawing process of freezing wall is obtained. The results show that it is feasible to apply hydraulic bag and hydraulic pressure together to achieve the effect of triaxial loading in closed space. During loading, the thickness of compression plate and the lateral pressure coefficient of soil have great influence on the loading effect. During the thawing process of freezing wall, the stress on the key points of the outside edge of the shaft wall is gradually increasing. Among them, the tension stress at the inner edge of the top arch is the largest and the radial displacement at the inner edge of the inverted arch is the largest. These two forces are in the most disadvantageous state at the key points of the shaft lining. In the design and construction of shaft lining structure, we should pay more attention to it. In the model test, the dimension of the steel model shaft wall is determined by numerical calculation. The hydrostatic loading test, the pure ground pressure loading test, the combined action of ground pressure and pore water pressure and the simulation test of wall force during the thawing process of freezing wall were carried out by using the model. It is found that in the hydrostatic pressure test, the influence of the circular steel head at both ends of the model shaft wall on the stress on the shaft wall is minimal, and the measured circumferential strain of the shaft wall is in good agreement with the numerical simulation results. The circumferential strain of the center of the inner edge of the inverted arch and the circumferential strain of the center of the inner edge of the top arch increase linearly with the increase of Y-direction load Yp. The larger the Xp is, the smaller the circumferential strain of the center of the inner edge of the inverted arch and the center of the inner edge of the top arch is. The circumferential strain of the inner edge of the inverted arch increases with the increase of the pore water pressure, and the circumferential strain of the inner edge of the top arch decreases with the increase of the pore water pressure in the combined test of ground pressure and pore water pressure. In the loading test of freezing wall during thawing stage, the temperature stress in the model shaft wall inhibits the pore water pressure and tensile stress in the center of the inner edge of the top arch and the center of the inner edge of the inverted arch during the thawing process of the frozen wall. The central circumferential strain of the top arch and the inverted arch gradually decreases with the increase of the freezing wall temperature, which is inconsistent with the results obtained by the numerical simulation. Finally, the main conclusions obtained by numerical simulation and model test are given, and suggestions for improvement are put forward in view of the deficiencies in the research process.
【學位授予單位】：中國礦業(yè)大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TD262
本文編號：2412986
[Abstract]:The stress of inclined shaft wall during thawing process is always a blind spot of inclined shaft construction project. With the freezing wall thawing, the inclined shaft wall is subjected to many fields, such as temperature field, moisture field, force field and so on. The research work at this stage is of great benefit to the design and construction of inclined shaft lining. Based on this, the method of numerical simulation and model test is used to study the force law of inclined shaft wall during thawing process of frozen wall in surface soil section. In the numerical simulation, the plane finite element model is established in combination with the test device, and the reliability of the hydraulic bag loading system is verified and calculated. On the basis of this, the single factor analysis of the related parameters that may affect the loading system is carried out. Finally, by using the method of sequential coupling, the coupling effect of temperature field and stress field is analyzed, and the force law of inclined shaft wall during the thawing process of freezing wall is obtained. The results show that it is feasible to apply hydraulic bag and hydraulic pressure together to achieve the effect of triaxial loading in closed space. During loading, the thickness of compression plate and the lateral pressure coefficient of soil have great influence on the loading effect. During the thawing process of freezing wall, the stress on the key points of the outside edge of the shaft wall is gradually increasing. Among them, the tension stress at the inner edge of the top arch is the largest and the radial displacement at the inner edge of the inverted arch is the largest. These two forces are in the most disadvantageous state at the key points of the shaft lining. In the design and construction of shaft lining structure, we should pay more attention to it. In the model test, the dimension of the steel model shaft wall is determined by numerical calculation. The hydrostatic loading test, the pure ground pressure loading test, the combined action of ground pressure and pore water pressure and the simulation test of wall force during the thawing process of freezing wall were carried out by using the model. It is found that in the hydrostatic pressure test, the influence of the circular steel head at both ends of the model shaft wall on the stress on the shaft wall is minimal, and the measured circumferential strain of the shaft wall is in good agreement with the numerical simulation results. The circumferential strain of the center of the inner edge of the inverted arch and the circumferential strain of the center of the inner edge of the top arch increase linearly with the increase of Y-direction load Yp. The larger the Xp is, the smaller the circumferential strain of the center of the inner edge of the inverted arch and the center of the inner edge of the top arch is. The circumferential strain of the inner edge of the inverted arch increases with the increase of the pore water pressure, and the circumferential strain of the inner edge of the top arch decreases with the increase of the pore water pressure in the combined test of ground pressure and pore water pressure. In the loading test of freezing wall during thawing stage, the temperature stress in the model shaft wall inhibits the pore water pressure and tensile stress in the center of the inner edge of the top arch and the center of the inner edge of the inverted arch during the thawing process of the frozen wall. The central circumferential strain of the top arch and the inverted arch gradually decreases with the increase of the freezing wall temperature, which is inconsistent with the results obtained by the numerical simulation. Finally, the main conclusions obtained by numerical simulation and model test are given, and suggestions for improvement are put forward in view of the deficiencies in the research process.
【學位授予單位】：中國礦業(yè)大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TD262
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，本文編號：2412986
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