【摘要】：煤炭對(duì)我國(guó)經(jīng)濟(jì)的發(fā)展有重要影響,我國(guó)是一個(gè)貧油少氣富煤的國(guó)家,煤炭是我國(guó)的主體能源。我國(guó)95%的煤炭通過井工開采方式采出,而礦井采掘活動(dòng)破壞了地下巖體原有的應(yīng)力平衡狀態(tài),引起應(yīng)力的重新分布,進(jìn)而引發(fā)巷道冒頂、片幫、底板鼓起等一系列礦山壓力現(xiàn)象的發(fā)生,影響工作面的正常生產(chǎn)。對(duì)于底鼓現(xiàn)象易發(fā)的巷道,礦車及機(jī)車運(yùn)輸方式不再適用,常常采用受巷道底板影響較小的單軌吊擔(dān)任工作面的輔助運(yùn)輸。然而,單軌吊載荷作用下,巷道頂板承受高集中應(yīng)力的作用,頂板的失穩(wěn)方式及支護(hù)機(jī)理均發(fā)生較大改變,結(jié)合綜放工作面的復(fù)雜應(yīng)力環(huán)境及綜放工作面巷道的空間位置布置方式對(duì)單軌吊巷道穩(wěn)定性的影響作用,單軌吊巷道頂板穩(wěn)定性的維持較為困難。本論文的研究依托于潞安礦業(yè)集團(tuán)余吾煤礦S1203綜放工作面,工作面地質(zhì)構(gòu)造簡(jiǎn)單,無頂板淋涌水現(xiàn)象,S1203工作面主采3#煤層:3#煤為黑色、塊狀構(gòu)造、節(jié)理發(fā)育、參差狀斷口,主要由亮煤組成,并夾有鏡煤暗煤條帶,屬光亮型煤。煤質(zhì)為特低硫、低磷、中灰、熱穩(wěn)定性好、高發(fā)熱量的優(yōu)質(zhì)動(dòng)力煤,其煤種為貧煤類,煤層瓦斯含量低。為了解決工作面回采過程中單軌吊作用下回采巷道頂板穩(wěn)定性的控制問題,本文進(jìn)行了S1203工作面回風(fēng)巷的頂板穩(wěn)定性控制技術(shù)研究。針對(duì)以上研究?jī)?nèi)容,通過數(shù)值模擬及理論分析手段得出區(qū)段煤柱、巷道布置方式及單軌吊載荷對(duì)頂板穩(wěn)定性的影響機(jī)理,并通過數(shù)值模擬研究綜放開采采場(chǎng)側(cè)向支承壓力及偏應(yīng)力第二不變量分布規(guī)律,對(duì)比分析支承壓力及偏應(yīng)力第二不變量得出單軌吊巷道區(qū)段保護(hù)煤柱的合理寬度;基于錨桿索預(yù)應(yīng)力場(chǎng)的分布結(jié)構(gòu)特征分析,提出巷道頂板支護(hù)的錨固復(fù)合深梁承載結(jié)構(gòu),并建立單軌吊作用下巷道頂板深梁穩(wěn)定性力學(xué)模型,分析頂板錨固復(fù)合深梁承載結(jié)構(gòu)的穩(wěn)定性影響因素,通過分析不同參數(shù)下深梁的受剪情況得出單軌吊巷道頂板合理的支護(hù)參數(shù),最終確定了單軌吊巷道的頂板支護(hù)方案,并進(jìn)行了現(xiàn)場(chǎng)礦壓觀測(cè)。本論文的研究主要取得了以下結(jié)論:(1)在分析余吾煤礦S1202及S1203工作面實(shí)際生產(chǎn)地質(zhì)條件及煤層賦存條件的基礎(chǔ)上總結(jié)得出回風(fēng)巷道頂板穩(wěn)定性的主要影響因素為巷道的留設(shè)方式、巷道與煤層的空間位置關(guān)系、單軌吊載荷。(2)通過對(duì)綜放開采下覆巖移動(dòng)特征的分析,建立了綜放開采條件下工作面老頂側(cè)向端部整體結(jié)構(gòu)模型,得出相鄰工作面開采對(duì)單軌吊巷道穩(wěn)定性的影響在于巷道圍巖的完整程度與應(yīng)力集中的相互矛盾。(3)通過數(shù)值模擬不同頂煤厚度條件下巷道圍巖的應(yīng)力場(chǎng)及位移場(chǎng)分布,得出頂煤厚度對(duì)巷道頂板穩(wěn)定性的影響規(guī)律為:頂板巖層水平應(yīng)力在頂板煤巖交界面處發(fā)生突變,水平應(yīng)力增大,煤巖交界面穩(wěn)定性差,隨頂煤厚度的增加,巷道頂板附加載荷值增大,塑形區(qū)范圍擴(kuò)張,巷道變形量增大。(4)運(yùn)用FLAC數(shù)值模擬軟件模擬了工作面?zhèn)认蛑С袎毫捌珣?yīng)力第二不變量隨煤柱寬度的變化規(guī)律,不同煤柱寬度條件下,支承壓力及偏應(yīng)力第二不變量具有相同的變化規(guī)律。煤柱寬度較小,即采用沿空留巷時(shí),煤柱內(nèi)部處于低支承壓力狀態(tài),應(yīng)力向深部轉(zhuǎn)移至巷道實(shí)體煤幫,巷道實(shí)體煤幫處于高集中應(yīng)力狀態(tài),但煤柱及巷道實(shí)體煤幫受相鄰工作面的采動(dòng)影響處于大范圍的塑形狀態(tài),巷道圍巖的完整性差,穩(wěn)定性低,自承能力差,不利于單軌吊作用下巷道頂板穩(wěn)定性的維持;隨煤柱寬度的增大,巷道及煤柱塑形區(qū)范圍逐漸收縮,巷道受相鄰工作面開采產(chǎn)生的應(yīng)力疊加作用減弱,巷道圍巖完整程度及兩幫應(yīng)力集中程度降低,維護(hù)難度降低。通過對(duì)S1202工作面?zhèn)认蛑С袎毫捌珣?yīng)力第二不變量進(jìn)行對(duì)比分析,得到偏應(yīng)力第二不變量對(duì)煤柱寬度選擇的指導(dǎo)作用,結(jié)合極限平衡理論下的煤柱寬度理論分析確定合理的煤柱寬度為30m。(5)通過分析巷道頂板的不同冒落形式得到單軌吊作用下巷道頂板的失穩(wěn)機(jī)理,結(jié)合數(shù)值模擬得出單軌吊對(duì)巷道圍巖位移場(chǎng)、應(yīng)力場(chǎng)及塑形區(qū)分布的影響,單軌吊使得巷道頂板的應(yīng)力及位移量增大,單軌吊載荷過大時(shí),模擬單元網(wǎng)格發(fā)生變形,有可能發(fā)生局部巖體的拉斷現(xiàn)象,因此,單軌吊作用下巷道頂板的維護(hù)重點(diǎn)為單軌吊懸吊區(qū)的淺部巖體。(6)通過對(duì)單軌吊作用下巷道頂板的穩(wěn)定性判據(jù)分析,提出了余吾礦S1203綜放工作面單軌吊回采巷巷道頂板總體的控制方向:應(yīng)從維持頂板巖層自身完整入手,避免因單軌吊載荷作用及開采擾動(dòng)導(dǎo)致的圍巖內(nèi)部原有裂隙的擴(kuò)展及新裂隙的產(chǎn)生,使單軌吊懸吊錨桿的錨固點(diǎn)位于完整的穩(wěn)定巖層中。(7)基于錨索預(yù)應(yīng)力作用下的預(yù)應(yīng)力場(chǎng)分布形態(tài),建立多錨索作用下的數(shù)值模擬模型,模擬結(jié)果表明:多錨索作用下的預(yù)應(yīng)力場(chǎng)近似為端部較窄,中部寬度較大的“鼓”形分布,輔以淺部錨桿的作用能夠使預(yù)應(yīng)力場(chǎng)呈近似的矩形狀,并且通過調(diào)節(jié)錨索的間排距及預(yù)緊力等參數(shù)能夠形成沿巷道軸向及切向均勻連續(xù)分布的預(yù)應(yīng)力場(chǎng),根據(jù)彈性力學(xué)的平面問題假設(shè)要求,提出預(yù)應(yīng)力錨桿索作用下的頂板錨固復(fù)合深梁承載模型。(8)建立了單軌吊作用下巷道頂板錨固復(fù)合深梁承載結(jié)構(gòu)簡(jiǎn)化力學(xué)模型,分別求得均布載荷、集中力作用下梁內(nèi)的應(yīng)力分布狀態(tài),通過應(yīng)力疊加法得出多載荷耦合作用下深梁內(nèi)部任一點(diǎn)的應(yīng)力分量,基于最大剪應(yīng)力強(qiáng)度準(zhǔn)則得到深梁的穩(wěn)定性求解公式。(9)通過對(duì)不同參數(shù)錨索作用下的預(yù)應(yīng)力場(chǎng)分布形態(tài)分析,得出錨索參數(shù)對(duì)預(yù)應(yīng)力場(chǎng)分布的影響規(guī)律,預(yù)應(yīng)力場(chǎng)范圍及應(yīng)力值大小與錨索長(zhǎng)度、間排距等錨索支護(hù)參數(shù)均為負(fù)相關(guān)關(guān)系,與錨索預(yù)緊力為正相關(guān)。(10)通過分析錨索預(yù)應(yīng)力場(chǎng)及頂板錨固復(fù)合深梁的相關(guān)關(guān)系,得到錨索長(zhǎng)度、間距及預(yù)緊力均為深梁穩(wěn)定性的復(fù)合影響因素。運(yùn)用MATLAB數(shù)值軟件計(jì)算得出單軌吊及錨索支護(hù)阻力作用下不同結(jié)構(gòu)尺寸深梁內(nèi)部最大剪應(yīng)力及預(yù)應(yīng)力場(chǎng)分布情況,以最大剪應(yīng)力近零應(yīng)力區(qū)及錨索預(yù)應(yīng)力擴(kuò)散系數(shù)為衡量指標(biāo)對(duì)深梁的穩(wěn)定性進(jìn)行量化分析,得到以下結(jié)論:單軌吊作用下,隨單軌吊載荷的增加,深梁內(nèi)部最大剪應(yīng)力高應(yīng)力區(qū)范圍擴(kuò)張,巷道淺部巖體的穩(wěn)定性降低;錨索預(yù)緊力不僅影響深梁內(nèi)部最大剪應(yīng)力分布還影響預(yù)應(yīng)力場(chǎng)的擴(kuò)散情況,結(jié)合兩者分析結(jié)果,高預(yù)緊力作用下深梁的穩(wěn)定性增加;深梁內(nèi)部最大剪應(yīng)力近零應(yīng)力區(qū)隨錨索間距為先增大后減小的變化趨勢(shì),但錨索間距的增加導(dǎo)致預(yù)應(yīng)力場(chǎng)擴(kuò)散效果的減弱及預(yù)應(yīng)力場(chǎng)沿巷道切向的差異程度升高。(11)結(jié)合現(xiàn)場(chǎng)實(shí)際情況,進(jìn)行現(xiàn)場(chǎng)試驗(yàn)研究,通過現(xiàn)場(chǎng)礦壓觀測(cè)結(jié)果分析,最終確定了單軌吊作用下綜放工作面回采巷道支護(hù)方案。單軌吊作用下的綜放工作面回采巷道頂板采用密集長(zhǎng)錨索支護(hù),錨索長(zhǎng)度為8300mm,間距900mm×900mm,預(yù)緊力200kN。在頂板打長(zhǎng)錨索進(jìn)行加固,使錨索錨固點(diǎn)處于未破壞的巖體內(nèi),借助錨索預(yù)應(yīng)力的擴(kuò)散作用使巷道表面軟弱圍巖及深部巖體形成復(fù)合錨固的深梁整體結(jié)構(gòu),輔以錨桿的作用對(duì)巷道淺部進(jìn)行加固,有效抑制單軌吊載荷作用下的應(yīng)力集中,控制巷道變形,提高其自身的穩(wěn)定性。
[Abstract]:Coal has an important impact on the development of China's economy. China is a country rich in oil and gas. Coal is the main energy source in China. 95% of the coal in China is extracted by underground mining, and the mining activities destroy the original stress balance of underground rock mass, causing the redistribution of stress, and then lead to roof caving in roadways and side-slicing. A series of mine pressure phenomena, such as floor heave, affect the normal production of the working face. For the roadway which is prone to floor heave, the transportation mode of mine truck and locomotive is no longer applicable. Monorail crane, which is less affected by the floor of the roadway, is often used as the auxiliary transportation of the working face. However, under the monorail crane load, the roof of the roadway bears high concentration. It is difficult to maintain the stability of monorail lifting roadway roof in combination with the complex stress environment of fully-mechanized caving face and the influence of spatial layout of roadway on the stability of monorail lifting roadway. The S1203 fully mechanized caving face of Yuwu Coal Mine of Yicheng Group has simple geological structure and no roof water gushing phenomenon. The main mining face of S1203 is 3# coal seam: 3# coal is black, massive structure, joint development, uneven fracture surface, mainly composed of bright coal, with dark coal band of mirror coal, belonging to bright briquette. Coal quality is very low sulfur, low phosphorus, medium ash, good thermal stability, high. In order to solve the problem of controlling the roof stability of roadway under the action of monorail crane in the process of working face mining, this paper studies the roof stability control technology of S1203 working face air return roadway. The influence mechanism of section coal pillar, roadway layout and monorail crane load on roof stability is obtained by analysis method. The distribution law of the second invariant of lateral supporting pressure and deviatoric stress in fully mechanized caving mining stope is studied by numerical simulation. The second invariant of supporting pressure and deviatoric stress is compared and analyzed, and the combination of protective coal pillar in monorail crane roadway section is obtained. Based on the analysis of structural characteristics of the prestressing field of anchor cables, the load-bearing structure of anchored composite deep beams in roadway roof support is put forward, and the mechanical model of the stability of roof deep beams under the action of monorail crane is established, the influencing factors of the stability of the load-bearing structure of roof anchored composite deep beams are analyzed, and the shear behavior of deep beams under different parameters is analyzed. In this paper, the main conclusions are as follows: (1) On the basis of analyzing the actual production geological conditions and coal seam occurrence conditions of S1202 and S1203 working faces in Yuwu Coal Mine, the paper summarizes and draws a conclusion. The main influencing factors of the stability of the roof of the return air roadway are the way of retaining the roadway, the space position relationship between the roadway and the coal seam, and the monorail lifting load. (2) Through the analysis of the movement characteristics of the overlying rock under the fully mechanized caving mining, the whole structure model of the lateral end of the main roof under the fully mechanized caving mining condition is established, and the monorail lifting roadway is obtained from the adjacent working face. The influence of roadway stability lies in the contradiction between the integrity of roadway surrounding rock and stress concentration. (3) Through numerical simulation of stress field and displacement field distribution of roadway surrounding rock under different roof thickness, the influence law of roof thickness on roadway roof stability is obtained as follows: horizontal stress of roof rock bursts at the interface of roof coal and rock. With the increase of the thickness of the top coal, the additional load value of the roof increases, the range of the plastic zone expands, and the deformation of the roadway increases. (4) The variation of the second invariant of the lateral supporting pressure and the deviatoric stress with the width of the coal pillar and the width of the coal pillar are simulated by FLAC numerical simulation software. The second invariant of supporting pressure and deviatoric stress has the same change rule under the condition of the condition that the width of coal pillar is small, that is, when the roadway is retained along the goaf, the coal pillar is in the state of low supporting pressure, and the stress is transferred to the roadway solid coal seam to the depth, and the roadway solid coal seam is in the state of high concentrated stress, but the coal pillar and roadway solid seam are subjected to the adjacent working face. The influence of mining is in a large range of plastic shape, the integrity of surrounding rock is poor, the stability is low, and the self-supporting capacity is poor, which is not conducive to the maintenance of the stability of the roof of the roadway under the action of monorail crane; with the increase of the width of coal pillar, the range of the roadway and the plastic zone of coal pillar gradually shrinks, the stress superposition effect of the roadway caused by mining in the adjacent working face is weakened, and the roadway is not conducive By comparing and analyzing the second invariant of lateral supporting pressure and deviatoric stress of S1202 working face, the guiding role of the second invariant of deviatoric stress on the selection of coal pillar width is obtained, and the reasonable coal pillar width is determined by combining the theoretical analysis of coal pillar width under the limit equilibrium theory. The column width is 30m. (5) The instability mechanism of the roadway roof under the action of monorail crane is obtained by analyzing the different caving forms of the roadway roof. Combined with the numerical simulation, the influence of monorail crane on the displacement field, stress field and plastic zone distribution of the roadway surrounding rock is obtained. The roof of roadway under monorail suspension is mainly maintained in shallow rock mass of monorail suspension area. (6) Based on the analysis of stability criterion of roadway roof under monorail suspension, the overall roof of monorail suspension mining roadway in S1203 fully mechanized caving face of Yuwu Coal Mine is put forward. Control direction: Maintaining the integrity of roof rock strata, avoiding the expansion of original cracks and the generation of new cracks in surrounding rock caused by monorail crane loading and mining disturbance, so that the anchorage point of monorail suspension anchor rod is located in a complete stable rock strata. (7) Based on the distribution pattern of prestressing field under the action of anchor cable prestressing, the construction of monorail suspension anchor rod is carried out. The numerical simulation results show that the prestressing field under the action of multi-anchor cables is approximately a narrow end and a large "drum" shape distribution in the middle of the cables, supplemented by the action of shallow anchors, can make the prestressing field approximate rectangular shape, and can form an edge by adjusting the parameters such as the distance between the cables and the pre-tightening force. The prestressing field distributed uniformly and continuously in the axial and tangential directions of the roadway is presented. According to the assumption of plane problem in elasticity, the bearing model of roof anchored composite deep beam under the action of prestressed anchor cable is put forward. (8) The simplified mechanical model of roof anchored composite deep beam bearing structure under the action of Monorail crane is established, and the uniform load and concentrated force are obtained respectively. Stress distribution in the beam under action is analyzed. Stress components at any point in the deep beam under multi-load coupling are obtained by stress superposition method. Stability formulas of the deep beam are obtained based on the maximum shear stress strength criterion. (9) By analyzing the distribution of prestressing field under different parameters of anchor cable, the prestressing force is calculated. The influence law of field distribution shows that the range of prestressing field and stress value are negatively correlated with the length of anchor cable and the distance between rows, and are positively correlated with the prestressing force of anchor cable. (10) By analyzing the correlation between the prestressing field of anchor cable and the composite deep beam anchored by roof, the length of anchor cable, the distance between anchor cable and the prestressing force are all stable of deep beam. The distribution of maximum shear stress and prestress field in deep beams with different structural sizes under the action of resistance of monorail crane and anchor rope is calculated by MATLAB. The stability of deep beams is quantitatively analyzed with the near zero stress zone of maximum shear stress and the diffusion coefficient of prestress of anchor rope as the evaluation index. The results are as follows. Conclusion: With the increase of monorail crane load, the range of maximum shear stress and high stress zone in deep beam expands, and the stability of rock mass in shallow roadway decreases. The pre-tension of anchor cable not only affects the distribution of maximum shear stress in deep beam, but also affects the diffusion of prestress field. The maximum shear stress near zero stress zone in deep beam increases firstly and then decreases with the anchor cable spacing, but the increase of anchor cable spacing leads to the weakening of prestressing field diffusion effect and the increase of prestressing field tangential difference along the roadway. (11) Combining with the actual situation in the field, the field test is carried out, and the field rock pressure observation is carried out. The roof of fully mechanized top-coal caving face under the action of monorail crane is supported by dense long anchor cable, the length of anchor cable is 8300 mm, the spacing is 900 mm 65 In rock mass, with the help of the diffusion of prestressing force of anchor cable, the weak surrounding rock and deep rock mass on the roadway surface form a composite anchored deep beam integral structure, and the shallow part of the roadway is reinforced by the action of anchor rod, which can effectively restrain the stress concentration under the load of monorail crane, control the deformation of the roadway and improve its own stability.
【學(xué)位授予單位】：中國(guó)礦業(yè)大學(xué)(北京)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2017
【分類號(hào)】：TD327.2

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相關(guān)期刊論文 前10條

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