本文選題：斜井 + 凍土�。� 參考：《中國礦業(yè)大學(xué)(北京)》2017年博士論文

【摘要】：本文充分運(yùn)用凍土試驗(yàn)、理論分析、數(shù)值模擬及現(xiàn)場工程實(shí)測等研究方法,測試了袁大灘礦井筒檢查孔地層樣品的主要物理力學(xué)特性參數(shù),分析了傾斜井筒凍結(jié)壁的應(yīng)力場演化規(guī)律,提出了斜井凍結(jié)壁穩(wěn)定性判別方法及塑性區(qū)分布和凍結(jié)壁厚度計(jì)算方法,推導(dǎo)出凍結(jié)壁內(nèi)部溫度分布方程和凍結(jié)壁外緣原始凍脹力計(jì)算方程。詳細(xì)探討了斜井凍結(jié)壁變形、塑性區(qū)分布與凍結(jié)壁力學(xué)參數(shù)、凍結(jié)壁幾何參數(shù)、凍結(jié)壁外載以及暴露時(shí)間等影響凍結(jié)壁穩(wěn)定的各主要因素之間的關(guān)系,并擬合出凍結(jié)壁收斂變形和塑性區(qū)分布的回歸計(jì)算式。現(xiàn)場實(shí)測了袁大灘礦主斜井去回路鹽水溫度、測溫孔溫度、凍結(jié)壁兩幫溫度、凍結(jié)壁收斂變形及壁后凍土壓力等參數(shù),分析了凍結(jié)壁形成后至解凍期間的穩(wěn)定性變化特征,總結(jié)出細(xì)砂層及粘土層的凍結(jié)壁徑向收斂變形大于粉砂巖層和砂質(zhì)泥巖層,主斜井凍結(jié)壁收斂變形產(chǎn)生差異的原因主要來自于凍結(jié)地層的強(qiáng)度特性變化等。本文以袁大灘礦主斜井凍結(jié)施工為背景,主斜井凍結(jié)壁穩(wěn)定性研究內(nèi)容及成果主要基于以下幾個(gè)方面:1.對袁大灘礦主斜井穿過地層巖土體進(jìn)行凍土物理力學(xué)特性試驗(yàn),測試了凍結(jié)土樣的質(zhì)量比熱、容積比熱、導(dǎo)熱系數(shù)、結(jié)冰溫度、凍脹率等參數(shù),并進(jìn)行了單軸壓縮和單軸蠕變試驗(yàn)。單軸試驗(yàn)結(jié)果表明,凍結(jié)表土單軸抗壓強(qiáng)度隨溫度降低近乎呈線性增長,強(qiáng)度增長速率約為0.32~0.64MPa/℃。凍結(jié)巖石單軸抗壓強(qiáng)度總體隨溫度降低而提高,-10℃~-15℃之間溫度對凍結(jié)巖石強(qiáng)度影響較大。低溫條件下凍結(jié)表土彈性模量受凍結(jié)溫度影響明顯,隨溫度降低不斷增加,增長速率約為0.874~12.97MPa/℃。低溫條件下凍結(jié)巖石彈性模量相對表土彈性模量要高,隨溫度降低總體呈現(xiàn)增長趨勢且離散性較大。低溫狀態(tài)下,凍結(jié)地層蠕變變形整體較小,應(yīng)力水平較低時(shí),基本上屬于衰減型蠕變,當(dāng)應(yīng)力水平較高時(shí),逐漸轉(zhuǎn)化為非衰減型蠕變。最后,通過建立凍土蠕變數(shù)學(xué)模型,并根據(jù)不同溫度條件下的軸向蠕變應(yīng)變與時(shí)間關(guān)系曲線獲得了各試驗(yàn)地層在不同溫度條件下各蠕變參數(shù)值。2.基于彈性力學(xué)理論,建立“傾斜彈性厚壁筒”力學(xué)模型,且考慮不同埋深條件,分析了凍結(jié)壁應(yīng)力場演化規(guī)律,計(jì)算出凍結(jié)壁的徑向應(yīng)力σ_r、環(huán)向應(yīng)力σ_θ、切向應(yīng)力τ_(rθ)及軸向應(yīng)力σ_τ的表達(dá)式,并從強(qiáng)度條件和變形條件兩方面提出凍結(jié)壁穩(wěn)定性判別方法。基于彈性狀態(tài)下凍結(jié)壁的應(yīng)力分布特征來確定其達(dá)到塑性狀態(tài)時(shí)的邊界線,并采用Mises屈服準(zhǔn)則來確定塑性區(qū)的屈服條件,給出凍結(jié)壁的最大塑性擴(kuò)展半徑及其厚度計(jì)算方法�；趫A管穩(wěn)定導(dǎo)熱方程建立雙孔凍結(jié)溫度場數(shù)學(xué)模型,利用疊加原理,推導(dǎo)出豎向直排三孔凍結(jié)壁溫度場分布方程和整排凍結(jié)壁內(nèi)部溫度方程,并對豎向多排斜井凍結(jié)壁的溫度場分布做出預(yù)測。按照內(nèi)緣凍脹力作用于外層井壁表面的方向,將其劃分為法向凍脹力、水平凍脹力和切向凍脹力,并總結(jié)了其分布特點(diǎn)。基于彈性力學(xué)理論,結(jié)合豎向直排孔的凍結(jié)帷幕特點(diǎn),建立凍脹力計(jì)算模型,根據(jù)凍結(jié)壁與未凍土之間的變形協(xié)調(diào)關(guān)系分析并得出凍結(jié)壁外緣原始凍脹力計(jì)算方法。3.通過對斜井凍結(jié)壁穩(wěn)定性的數(shù)值模擬研究,分析了凍結(jié)壁收斂變形、塑性區(qū)分布與凍結(jié)壁力學(xué)參數(shù)、凍結(jié)壁幾何參數(shù)、凍結(jié)壁外載以及暴露時(shí)間等影響凍結(jié)壁穩(wěn)定的各主要參數(shù)之間的關(guān)系,擬合出計(jì)算指標(biāo)與多因素回歸方程。斜井凍結(jié)壁收斂變形和塑性區(qū)分布范圍主要受凍結(jié)壁強(qiáng)度、凍結(jié)壁厚度、井筒掘進(jìn)尺寸、開挖段長、凍結(jié)壁外荷載以及暴露時(shí)間等多重因素綜合影響。影響斜井凍結(jié)壁收斂變形和塑性區(qū)分布范圍的主要因素為凍結(jié)壁所承受的頂板荷載、水平荷載以及凍結(jié)壁的強(qiáng)度,其次是開挖段長和暴露時(shí)間,而凍結(jié)壁厚度對凍結(jié)壁收斂變形和塑性區(qū)分布范圍的影響程度比較復(fù)雜,主要與外載水平和當(dāng)前厚度相關(guān)。外載水平變化時(shí),凍結(jié)壁厚度對凍結(jié)壁收斂變形的影響并不顯著,但對凍結(jié)壁塑性區(qū)分布范圍的影響則較大;開挖段長對凍結(jié)壁收斂變形和塑性區(qū)分布范圍的影響與凍結(jié)壁外荷載水平相關(guān);凍結(jié)壁暴露時(shí)間對凍結(jié)壁收斂變形和塑性區(qū)分布范圍的影響主要體現(xiàn)在凍結(jié)壁暴露初期,隨變形時(shí)間的增大收斂變形和塑性區(qū)分布成線性增長。在凍結(jié)壁空幫段上,凍結(jié)壁頂板變形大于底板變形,左右兩幫變形對稱,最大頂?shù)装遄冃魏妥畲髢蓭妥冃尉l(fā)生在距離工作面迎頭0.45倍段長處,且靠近工作面迎頭和已支護(hù)段兩端,變形量逐漸減小。凍結(jié)壁頂板塑性區(qū)分布范圍較大,底板塑性區(qū)分布較少;左右兩幫塑性區(qū)分布整體上對稱,且靠近工作面迎頭和已支護(hù)段方向上塑性區(qū)分布逐漸增大。為了獲得更加安全、經(jīng)濟(jì)、穩(wěn)定的凍結(jié)壁,當(dāng)井筒的開挖尺寸確定時(shí),必須明確不同地段、不同深度凍結(jié)壁所承受的外荷載,從而提高凍土強(qiáng)度,并結(jié)合施工工藝和進(jìn)度安排合理確定開挖段長。井筒掘進(jìn)開挖時(shí),在距離工作面迎頭0.45倍段長處,應(yīng)對圍巖采取加強(qiáng)支護(hù)措施,防止圍巖發(fā)生突然垮落。同時(shí),片面增加凍結(jié)壁厚度并沒有太大意義,確定凍結(jié)壁厚度時(shí),應(yīng)對井筒掘進(jìn)尺寸、開挖段長、凍結(jié)壁強(qiáng)度、外載水平及變形時(shí)間等因素進(jìn)行綜合分析。4.開展現(xiàn)場條件下的工程實(shí)測研究,實(shí)測內(nèi)容主要包括:去回路鹽水溫度、測溫孔溫度、凍結(jié)壁兩幫溫度、凍結(jié)壁收斂變形及壁后凍土壓力等指標(biāo),并結(jié)合實(shí)測結(jié)果對凍結(jié)壁穩(wěn)定性進(jìn)行分析。根據(jù)實(shí)測的去回路鹽水系統(tǒng)溫度、測溫孔溫度、凍結(jié)壁兩幫溫度計(jì)算出凍結(jié)壁的平均溫度。監(jiān)測結(jié)果表明,凍結(jié)壁溫度基本滿足工程設(shè)計(jì)要求。凍結(jié)壁收斂變形實(shí)測結(jié)果表明,凍結(jié)壁的徑向變形不僅與凍結(jié)壁土層埋深有關(guān),同時(shí)與土層性質(zhì)密切相關(guān)。在細(xì)砂層與粉砂巖層附近及粘土層與砂質(zhì)泥巖層附近,凍結(jié)壁的徑向收斂變形均有大幅降低,細(xì)砂層及粘土層的凍結(jié)壁徑向收斂變形大于粉砂巖層和砂質(zhì)泥巖層。凍結(jié)壁的收斂變形速率實(shí)測結(jié)果與按照數(shù)值模擬回歸公式計(jì)算得到的凍結(jié)壁收斂速率基本一致,(?)_v/V_v的波動范圍為0.75~1.69,(?)_v/V_v波動范圍為0.71~3.17,實(shí)測值與計(jì)算值相差不大。通過凍結(jié)壁的頂、腳、底三處的斜井井壁的受力監(jiān)測,分析了內(nèi)層井壁形成后至解凍期間凍結(jié)壁的穩(wěn)定性變化特征。井壁最大壓力出現(xiàn)在拱頂,底板與拱腳壓力都很小。在壓力測試元件埋設(shè)約70~80d左右之后,凍結(jié)壁承載能力逐漸下降,直至完全解凍后,承載能力完全喪失。袁大灘礦主斜井凍結(jié)壁收斂變形產(chǎn)生差異的原因主要來自于各凍結(jié)地層凍結(jié)壁的強(qiáng)度不同,在類似條件的凍結(jié)壁設(shè)計(jì)過程中,當(dāng)凍結(jié)壁厚度、開挖段長和暴露時(shí)間等因素確定時(shí),可按照強(qiáng)度條件來判定凍結(jié)壁的穩(wěn)定性。
[Abstract]:In this paper, the main physical and mechanical properties of the samples are tested by the methods of frozen soil test, theoretical analysis, numerical simulation and field engineering measurement. The evolution law of the stress field of the frozen wall of the inclined shaft is analyzed. The stability discrimination method for the frozen wall of the inclined shaft and the distribution and freezing of the plastic zone are put forward. The equation of the temperature distribution inside the frozen wall and the calculation equation of the original frost heaving force on the outer edge of the frozen wall are derived, and the key factors affecting the stability of the frozen wall are discussed in detail, such as the deformation of the frozen wall, the distribution of the plastic zone and the mechanical parameters of the frozen wall, the geometric parameters of the frozen wall, the loading of the frozen wall and the exposure time. The regression calculation formula of the convergence deformation and the plastic zone distribution of the frozen wall is fitted, and the parameters such as the temperature of the salted water in the main inclined shaft of Yuanda beach, the temperature of the temperature of the temperature of the temperature of the temperature of the temperature of the freezing wall, the convergent deformation of the frozen wall and the pressure of the permafrost after the wall are measured, and the characteristics of the stability change during the freezing wall form to the thawing are analyzed. The radial convergence deformation of the frozen wall of the fine sand layer and the clay layer is larger than the silt rock and the sandy mudstone layer. The reasons for the difference of the convergence and deformation of the main inclined shaft are mainly due to the change of the strength characteristics of the frozen strata. Based on the following aspects: 1. the physical and mechanical properties of the main inclined shaft of Yuan datan mine through the stratum rock and soil were tested, and the parameters of the mass specific heat, the volume specific heat, the thermal conductivity, the freezing temperature and the frost heave rate were tested, and the uniaxial compression and uniaxial vermicular test were carried out. The uniaxial test results showed that the frozen topsoil was uniaxial compression. The strength increased almost linearly with the temperature, and the strength growth rate was about 0.32~0.64MPa/ C. The uniaxial compressive strength of the frozen rock increased with the temperature, and the temperature between -10 C and ~-15 C had great influence on the strength of the frozen rock. The growth rate is about 0.874~12.97MPa/ C. At low temperature, the modulus of elasticity of frozen rock is higher than that of surface soil. The overall growth trend and dispersion are larger with the temperature decreasing. Under low temperature, the creep deformation of frozen stratum is smaller and the stress level is low, it is basically attenuated creep, and when the stress level is high, the stress level is higher. In the end, by establishing the mathematical model of frozen soil creep, and according to the relation curve of the axial creep strain and time under different temperature conditions, the creep parameter values of each test stratum under different temperature conditions.2. are based on the elastic mechanics theory, and the mechanical model of "inclined elastic thick wall cylinder" is set up, and it is not considered. On the same buried depth condition, the evolution law of the stress field of the frozen wall is analyzed. The expressions of the radial stress Sigma _r, cyclic stress sigma, R theta and the axial stress sigma are calculated, and the formula for the stability of the frozen wall is put forward from two aspects of the strength condition and the deformation condition. The boundary line when it reaches the plastic state is determined, and the yield condition of the plastic zone is determined by the Mises yield criterion. The maximum plastic expansion radius and the thickness calculation method of the frozen wall are given. Based on the stable heat conduction equation of the circular tube, a mathematical model of the freezing temperature field of the double hole is established, and the vertical straight row three hole freezing wall temperature is derived by the superposition principle. The temperature field distribution equation of the degree field and the internal temperature equation of the whole frozen wall are predicted, and the temperature distribution of the freezing wall of the vertical multi row inclined shaft is predicted. According to the direction of the inner edge frost heaving force acting on the surface of the outer well wall, it is divided into the normal frost heaving force, the horizontal frost heaving force and the tangential frost heaving force, and the distribution characteristics are summed up. Based on the elastic mechanics theory, the conclusion is made. The frost heaving force calculation model is set up with the characteristics of the freezing curtain of vertical straight holes. According to the analysis of the deformation coordination relationship between the frozen wall and the unfrozen soil, the calculation method of the original frost heaving force of the outer edge of the frozen wall is obtained by the numerical simulation of the stability of the frozen wall of the inclined shaft, and the deformation of the frozen wall, the distribution of the plastic zone and the frozen wall force are analyzed by the numerical simulation of the stability of the frozen wall of the inclined shaft. The relationship between the parameters of the parameters, the geometric parameters of the frozen wall, the load of the frozen wall and the exposure time, etc., which affect the stability of the frozen wall, and fitting out the calculation index and the multiple factor regression equation. The convergence and the plastic zone distribution of the frozen wall of the inclined shaft are mainly frozen wall strength, the thickness of the frozen wall, the bore size of the shaft, the length of the excavation section and the freezing. The main factors affecting the convergence and plastic zone distribution of the frozen wall of the inclined shaft are the roof load, the horizontal load and the strength of the frozen wall, followed by the length of the excavation section and the exposure time, while the thickness of the frozen wall is distinguished from the convergence deformation and plasticity of the frozen wall. The influence degree of the cloth range is complex, mainly related to the load level and the current thickness. The effect of the thickness of the frozen wall on the convergence deformation of the frozen wall is not significant, but it has great influence on the distribution of the plastic zone of the frozen wall; the influence of the length of the excavation length on the convergence deformation and the plastic zone distribution of the frozen wall and the frozen wall The influence of the exposure time of the frozen wall on the convergence deformation and the plastic zone distribution of the frozen wall is mainly reflected in the early stage of the freezing wall exposure, with the increase of the deformation time and the linear growth of the plastic zone. On the frozen wall space section, the deformation of the roof of the frozen wall is greater than that of the bottom plate, and the two sides of the frozen wall are symmetrical. The deformation of the maximum top floor and the maximum two groups of deformation occur at the length of 0.45 times the length of the head-on face of the working face, and the deformation is gradually reduced. The plastic zone distribution of the roof of the frozen wall is larger, the plastic zone of the floor is less distributed, and the distribution of the plastic zone of the left and right two groups is symmetrical and close to the face of the working face. The distribution of plastic zone in the direction of the support section is increasing gradually. In order to obtain more safe, economical and stable frozen wall, when the excavation size of the shaft is determined, it is necessary to clear the external load under the frozen wall of different sections and different depths, so as to improve the strength of the frozen soil, and to rationally determine the length of the excavation section with the construction technology and schedule. During the excavation, 0.45 times the length of the face from the face of the working face, the strengthening measures should be taken to prevent the sudden collapse of the surrounding rock. At the same time, it is not of great significance to increase the thickness of the frozen wall unilaterally. When the thickness of the frozen wall is determined, the dimensions of the shaft heading, the length of the excavation section, the strength of the frozen wall, the level of the external load and the time of the deformation should be taken into account. On the basis of the comprehensive analysis of.4., the actual measurement research under field conditions is carried out. The main contents are as follows: the temperature of the salted water, the temperature of the temperature of the temperature of the temperature of the temperature of the temperature of the temperature of the freezing wall, the convergent deformation of the frozen wall and the pressure of the permafrost after the wall, and the stability of the frozen wall is analyzed with the measured results. The average temperature of the freezing wall is calculated at the temperature of the temperature hole and the freezing wall two. The monitoring results show that the freezing wall temperature is basically satisfied with the engineering design requirements. The measured results of the convergence deformation of the frozen wall show that the radial deformation of the frozen wall is not only related to the buried depth of the frozen wall soil, but also closely related to the soil layer properties. Near the clay layer and the sandy mudstone layer, the radial convergence deformation of the frozen wall is greatly reduced. The radial convergence deformation of the frozen wall of the fine sand layer and the clay layer is larger than the silt and the sandy mudstone. The convergence rate of the frozen wall is basically the same as the calculation of the convergence rate of the frozen wall calculated by the numerical simulation regression. The fluctuation range of (?) _v/V_v is 0.75~1.69, and the range of (?) _v/V_v fluctuation is 0.71~3.17. The measured value is different from the calculated value. The stability change characteristics of the frozen wall during the formation of the inner wellbore to the thawing are analyzed by the force monitoring of the wall of the inclined shaft at the top of the frozen wall, the foot and the bottom three. The maximum pressure of the shaft wall appears in the vault, the floor and the floor. The pressure of the arch foot is very small. After the pressure test element is buried about 70~80d, the bearing capacity of the frozen wall gradually decreases, and the bearing capacity is completely lost after the complete thawing. The reasons for the difference of the convergence deformation of the frozen wall of the main slope of Yuanda beach mainly come from the different freezing wall strength of the frozen strata and the frozen wall in similar conditions. In the design process, when the factors such as the thickness of the frozen wall, the length of the excavation section and the exposure time are determined, the stability of the frozen wall can be determined according to the strength conditions.
【學(xué)位授予單位】：中國礦業(yè)大學(xué)(北京)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2017
【分類號】：TD265.3

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