采礦專業(yè)中英文文獻(xiàn)翻譯關(guān)于傾角煤層挖掘巷道的錨桿支護(hù)的研究.pdf

本科畢業(yè)設(shè)計(jì) 論文 通過答辯 原文 study on gateway bolting excavated in inclined coal seam tao lianjin 陶連金 wang yongjia 王永嘉 zhan zhuoyuan 張倬元 northeastern university shenyang 110006 chengdu university of technology chengdu 610059 abstract a typical gateway is analyzed using fully deformable discrete element method the fractured zone around the gateway is measured in field based on the measurement results and theoretical analysis a comprehensive support scheme adopting bolt and steel belt is proposed discrete element method is used to asses the bolting scheme and displacement monitoring in field is also carried out having been put into practice it is proved that the scheme is both successful and rational according to theoretical analysis and monitoring in filed some important keynotes that should be noticed in gateway bolting practice are presented as well keywords inclined seam gateway strata behavior bolting discrete element method introduction inclined coal seam is generally regarded as seam with a dip single 25 45 o which occupies a considerable proportion in both production and reserves in china problems related to strata control are however seldom studied and researches on in seam gateway are even 1 less the maintenance expense of gateway in inclined seam is generally 30 higher than that in nearly flat and gently inclined seam the reason why there exists a such phenomenon is complicated itself another possible reason is the lack of the inherent strata behavior law at present problems related to in seam gateway maintenance are highly emphasized and many studies on strata behavior and support of gateway are carried 2 4 out such researches play a positive role in gateway maintenance however most of the researches are carried out in flat or gently inclined seams due to their locating in remarkably anisotropic media and environment gateways in inclined seams are often subjected to unfavorable loads and deform unevenly strata move more intensively than that in gently inclined seam and the broken region is also large which makes gateway support even more difficult in view of the above mentioned facts we use fully deformable discrete element method in simulating strata behavior of gateway in inclined seam and the loosed zone around the gateway is also monitored in field based on the results a bolting scheme is proposed after putting into practice the scheme is proved to be effective and rational 1 deform and fail features of gateway without any support 本科畢業(yè)設(shè)計(jì) 論文 通過答辯 1 1 geologic conditions the study object is the no 36 seam in baoshan coal mine the dip angle of the seam is 35 and thickness is 1 0m the geologic conditions are rather simple the average buried depth is 440m the immediate roof is 2 meters thick of fine sandstone and shale the overall strength is low above the immediate roof is comparatively hard main roof the floor is fine sandstone the gateway width is 2 2m and the gateway is excavated in irregular shape in order to keep the roof intact the sidewall coal is however rather soft and loose and easily fails the surrounding rocks of the gateway are not stable roof and sidewall are apt to fall or break which is dangerous to both production and human safety the working face often stopped due to difficult maintenance of the gateways 1 2 simulation of gateway deformation and failure with discrete element method the joint statistical results show that the surrounding rocks of the gateway are cut by two orthogonal joints one group is the bedding plane of the coal measures another group is normal to the bedding plane mainly developed in the immediate roof because of the low strength of immediate roof there often exist long joints that cross through the immediate roof such long joints play a dominant part in roof falling according to the spatial distribution of joints a discrete element model is built as shown in fig 1 thecomputing parameters required are mainly based on measurement in field and some back analysis the load applied to the model are gravitational stress field the discrete elements are fully deformable so that he deformation of block can be involved after the gateway is excavated under the action of initial stresses the upper sidewall coal firstly breaks then the surface of the lower sidewall coal begins to yield the abutments of the roof at the two sidewall transfer to deep solid coal in consequence the immediate roof at the surface of the gateway begins to bend bedding separate fail and fall see fig 2 as a result large area of the roof falls until up to the main roof some broken blocks may collapse when a small disturbance occurs in the practical face it is very difficult to deal with the fallen rocks sometimes a chain collapse of upper immediate roof may occur if special attention is not paid which makes the fallen rock disposal a difficult and dangerous task 本科畢業(yè)設(shè)計(jì) 論文 通過答辯 the results indicate that two sidewall coals fail differently the upper coal breaks more intensively than the lower sidewall coal according to the above mentioned analysis it can be seen that in middle to lowly hard thin inclined seam the stability of the two sidewall coals is very important to the overall stability of the gateway if the sidewall fails then the abutments of the roof will transfer to deep solid coal as a result the free span of the roof increases which aggravates the unstable condition of the whole gateway such failure of surrounding rocks is even serious when it is subjected to mining influence it is thus the key to keep the sidewall solid and intact in order to keep the overall stability of gateway in inclined seams 2 measurement of loosed zone around gateway based on loosed zone theory of excavation a loosed zone is generally formed around the excavation if which the stress is lower than the initial stress owing to irregular shape of gateway in inclined seam and anisotropic media the loosed zone around gateway is certainly in irregular shape we use an ultrasonic joint detector type sc ii by fushun institute of coal science and technology to measure the loosed zone of the gateway the test results are shown in fig 3 the gateway was supported by two roof bolts 1 6m long with very slightly prestressed the measured loosed zone is upper sidewall coal more than 1 8m lower sidewall coal 1 4 1 5m and the roof is 0 95 1 1m 本科畢業(yè)設(shè)計(jì) 論文 通過答辯 the gateway can be stable without mining influence but as long as being subjected to mining activity the gateway will collapse wit sidewall failing and roof falling in extreme case the maximum caving height can reach as high as 4 0m as a result the gateway in the seam is very difficult to be maintained and the maintenance cost is thus rather high the test results are coincided with the numerical calculation so it is therefore necessary to reinforce the gateway including the sidewall comprehensively 3 inclined combined beam model for roofbolts in inclined seam roofbolts combine roof together when bolt length is shorter than the soft and loose roof of course if the bolt can be bolted at a competent stratum then the bolting mechanism will become hanging over a typical inclined combined beam model is illustrated in fif 4 the beam is composed by several total numbers of layers are k different kinds of strata with length l and thickness it is assumed that 1 each layer of the beam is homogeneous continuous and isotropic 2 the beam conforms to small deformation and 3 each layer deforms together and no slip along bedding occurs according to strength criteria of the beam the minimum thickness can be derived and then the total length of a bolt can be easily determined as follows 12 lll 1 where 1 l is the length of bolted end 2 l is the length of outer part bolt spacing a can be derived by the criteria that no slip occurs along bedding planes besides the above mentioned conditions the safety of the combined beam must be checked to prevent it from longitudinal instability when all the conditions are satisfied roof bolt parameters can ready be 本科畢業(yè)設(shè)計(jì) 論文 通過答辯 determined as for sidewall bolts their length and spacing can be derived by soil bracing theory in soil mechanics it should be noticed when roof is composed of weak and loose strata some bracing measures must be taken to protect the integrity of the fragile roof 4 bolting of the gateway and its assessment 4 1 support assessment by discrete element method we consider two case in order to compare first case only the roof is bolted second case both roof and sidewall are bolted having been bolted in the first case the roof has a obvious higher stiffness and strength in the initial stage only slight deflection occurs however with the sidewall coal failing and caving the free span of the roof increases the roof gradually enters unstable stage subsiding and bedding separating as shown in fig 5 compared with the unsupported gateway the gateway with roof bolted can keep stability for much longer time even it destabilizes finally in the second case the sidewall coal deformation and failure are strictly controlled by the sidewall bolts the sidewalls are stable roof deflects only a small amount displacement can be hardly seen in the block diagram fig 6 the overall surrounding strata are in stable conditions even influenced by mining activity the gateway only fails locally the roof is however rather stable it is thus important to adopt a comprehensive bolt support pattern including the sidewalls 4 2 bolting scheme and its implementation based on the inclined combined beam theory gateway loosed zone measurement and discrete element analysis four bolts 1 6m long are installed in the roof at the outer end of each bolt a testing device is installed 5 patent of national bureau of china to ensure that at least 20kn pretension is exerted bolt spacing is 0 75m array pitch is 1 0m due to rather developed joints steel bends are used together with roof bolt to ensure support effectiveness and prevent local roof caving the steel plate is 本科畢業(yè)設(shè)計(jì) 論文 通過答辯 0 01m thick 0 89m long and 0 1m wide the coal sidewall is reinforced by timber bolt with spacing 1 0m timer bolt for upper sidewall is 2 0m long and 1 0m for the lower sidewall the timber bolt is installed with no less 7 5kn pretension in the influence zone of front abutment pressure strengthened supports are added metal frictional prop with timber cap is set as temporary reinforcement the reinforcement distance is 25m ahead of the working face the reinforced props are arranged in the center line of the gateway more attentions should be paid to gateway excavation procedure the roof bolts should be installed as soon as possible after the roof is exposed then the sidewall bolt the maximum delayed time should be less than 6 hours which can make the roof deform exceedingly and integrity worsening after each construction cycle the bolts near the driving face should be refastened to assure their anchorage force 4 3 measurement of gateway closure in order to assess the effectiveness of the support scheme the gateway closure is monitored during its driving and working face retreating the closure of roof vs floor sidewalls and roof subsiding velocity are shown in fig 7 it can be seen that when the working face is far away from the monitoring area the deformation of the surrounding rocks is very small indicating that the gateway is not influenced by face dynamic pressure the support system can easily bear the static load of gateway itself with the working face advancing the gateway begin to sense the dynamic action of the working face when the distance between the face and monitoring area is around 20 meters the deforming velocity of surrounding is increasing obviously and the strata is moving remarkably such response of the gateway is the dynamic action of the working face the testing results show that the reinforced distance should be more than 20 meters however from the overall status of the surrounding rock the gateway is in stable conditions and can satisfy the demand of coal transportation air intake and other engineering function in spite of the fact that there are 2 3 groups of joints distinctively shown if the roof the roof is however stable under the combined action of roof bolts and steel bens the upper sidewall coal fails and falls in some places but the depth is limited 本科畢業(yè)設(shè)計(jì) 論文 通過答辯 within 0 6m based on the facts in field in brief the support scheme is rational and effective good economic and rechnical benefit were obtained 5 conclusion the failure pattern of gateway in inclined seam is remarkably anisotropic the failure zone is not only related to the mechanical properties of strata but also closely to the stability of sidewall coal body the sidewall coal failure causes the abutment points to transfer into deep solid coal increase the free span of the roof and therefore worsen the roof integrity it is thus a key task to keep the gateway sidewall sound in gateway maintenance by gateway loosed zone testing combined with the inclined combined beam model bolt parameters can be readily determined discrete element method can be adopted to verify the rationality and make some amendment as for the roof with multiple soft and loose layers ensuring bolt pretension and installing roof bolts as early as possible are the keys to make the roof stable meanwhile to keep roof integrity with steel bends sometimes metal net is needed is another important measure it is proved that bolting can be use in gateway with fragile and weak roof as long as necessary measures are taken considerable economic benefit can be obtained references 1 陶連金 大傾角煤層開采礦山壓力顯現(xiàn)及其控制 學(xué)位論文 沈陽 東北大 學(xué) 1996 70 79 2 候朝烔 郭宏亮 我國煤巷錨桿動手術(shù)的發(fā)展方向 煤炭學(xué)報(bào) 1996 21 2 113 118 3 陳炎光主編 中國煤礦巷道圍巖控制 徐州 中國礦業(yè)大學(xué)出版社 1995 3 4 67 70 4 陶連金 寶山煤礦巷道圍巖松動范圍測試 建井技術(shù) 1993 3 4 67 70 5 劉明遠(yuǎn) 陶連金 李芳成等 錨桿預(yù)緊力標(biāo)示圈 1993 國家專利號 93208997 6 本科畢業(yè)設(shè)計(jì) 論文 通過答辯 中文譯文 關(guān)于傾角煤層挖掘巷道的錨桿支護(hù)的研究 關(guān)于傾角煤層挖掘巷道的錨桿支護(hù)的研究 摘要摘要 一種典型的巷道是使用完全可變形的離散元素法 巷道周圍的斷裂區(qū) 域是有規(guī)則的 在測量結(jié)果和理論分析的基礎(chǔ)上 一種全新的使用錨桿和鐵板的 支護(hù)方案被提出 離散元素法被用于評估錨桿支護(hù)方案 并且取代了在現(xiàn)場上經(jīng) 常采用的監(jiān)測手段 自從投入到實(shí)際應(yīng)用以來 這種方案被證實(shí)是成功的和正確 的 對于理論分析和現(xiàn)場的監(jiān)測 一些在巷道螺栓連接的實(shí)踐中必須被注意的關(guān) 鍵點(diǎn)最好還是總結(jié)一下 關(guān)鍵詞關(guān)鍵詞 傾斜地層 巷道 地層運(yùn)動 錨桿支護(hù) 離散元素法 概述概述 傾角煤層一般是指煤層有一個(gè) 25 到 45 的下沉角度 這種煤層在中國的產(chǎn)量 和儲存量中占有相當(dāng)大的比例 涉及到地層控制的問題 很少被研究 并且研究 地層巷道的學(xué)者就更少了 維護(hù)傾斜煤層巷道的費(fèi)用一般來說比近似平直和逐漸傾斜的煤層巷道的費(fèi) 用要高百分之三十 導(dǎo)致出現(xiàn)這種現(xiàn)象的原因一是自身的復(fù)雜情況 另一個(gè)是基 本的地層運(yùn)動理論 目前 關(guān)于煤層巷道的維護(hù)問題已經(jīng)引起關(guān)注 并且許多關(guān)于地層運(yùn)動和巷 道的支撐的研究已經(jīng)展開了 這些研究在巷道的維護(hù)過程中 起到了積極的作用 然而 大多數(shù)研究是圍繞平直或者是逐漸傾斜的煤層展開的 由于他們是定 位在非常特殊的各有異性的媒介和環(huán)境中的 而在傾斜煤層的巷道通常受到不利 的載荷并且不均衡的產(chǎn)生變形 地層運(yùn)動比逐漸傾斜的煤層要強(qiáng)烈 另外遭到破 壞的區(qū)域也是很大的 這就造成了巷道的支撐更加困難 從以上提到的情況來看 我們在仿真傾斜煤層巷道的地層運(yùn)動中使用了完全 可變形離散元素法 并且在巷道的承載小的區(qū)域也被監(jiān)控起來 基于這些監(jiān)控結(jié) 果 一種螺栓連接的方法被提出 等到付諸實(shí)踐以后 這種方法被證明是有效的 并且是合理的 1 沒有任何支撐的巷道的變形和實(shí)效特征沒有任何支撐的巷道的變形和實(shí)效特征 1 1 地質(zhì)條件地質(zhì)條件 研究對象是寶山煤礦的第 36 號煤層 煤層的向下傾角是 35 度 煤層厚度是 1 米 地質(zhì)條件是相當(dāng)簡單的 平均的埋藏深度是 440 米 巷道上緊接著的頂 是 2 米厚的沙巖和頁巖 施加全部的載荷是低的 再一層是比較硬的重要的頂 這一層是沙巖 巷道的寬度是 2 2 米并且為了保持頂不被改變 巷道被以不規(guī)則 的形狀挖掘 邊墻的煤卻是又軟又松 很容易掉下來 巷道周圍的巖石不是很穩(wěn) 定 頂和邊墻易于倒下或者斷裂 這對于煤炭生產(chǎn)和礦工的安全都是一個(gè)隱患 工作進(jìn)程經(jīng)常由于巷道的困難得維護(hù)而停止 1 2 用離散元素法來仿真巷道的變形和失效用離散元素法來仿真巷道的變形和失效 接縫的統(tǒng)計(jì)結(jié)果表明巷道的圍巖是被兩個(gè)垂直的接縫破壞的 一條是煤礦測 量的基床 另一條是垂直于基床的 主要發(fā)生在緊鄰的頂 由于緊鄰頂?shù)牡蛷?qiáng)度 常常會出現(xiàn)穿透緊鄰頂?shù)拈L裂縫 這么長的裂縫是冒頂事故發(fā)生的主要原因 按 照裂縫的空間分布 建立起一個(gè)如圖 1 的離散元素模型 計(jì)算所需要的參數(shù)主要 基于現(xiàn)場的測量和一些后續(xù)的分析 模型實(shí)際的負(fù)載是重力 這些離散元素是完 全可變的 因此巖石的變形可以被考慮在內(nèi) 本科畢業(yè)設(shè)計(jì) 論文 通過答辯 當(dāng)巷道被挖掘好以后 在處應(yīng)力的作用下 上方邊墻的煤層首先破裂 接著 下方邊墻的煤層的表面開始屈服變形 結(jié)果兩個(gè)邊墻的間的頂?shù)闹巫兂缮顚拥?堅(jiān)實(shí)的煤層 在巷道表面的緊鄰的頂開始彎曲變形 基床分離 失效并且掉落 如 圖 2 結(jié)果大面積的頂?shù)袈?直到到主頂 當(dāng)一個(gè)小震動發(fā)生時(shí) 一些破碎的 巖石可能倒塌 實(shí)際上 掉落的巖石很難處理 有時(shí)如果沒有特別關(guān)注 上方緊 鄰頂可能會發(fā)生一系列倒塌 那會使掉落巖石的處理成為一項(xiàng)困難并且危險(xiǎn)的任 務(wù) 圖 1 離散元素模型的巖石分割 圖 2 巷道周圍圍巖的狀況 結(jié)果表明兩個(gè)邊墻煤層的失效是不同的 上方的煤層比下方煤層更容易破 裂 按照上面提到的分析 可以看出在中間對于低的薄硬傾斜煤層 兩個(gè)邊墻煤 層的穩(wěn)定性對于整個(gè)巷道的穩(wěn)定性是非常重要的 如果邊墻失效 接著頂?shù)闹?將會變成深層的堅(jiān)實(shí)的煤層 結(jié)果頂?shù)淖杂煽缇嘣黾?這樣會加大整個(gè)巷道的不 穩(wěn)定性 當(dāng)受到采煤的影響時(shí) 圍巖的失效會更嚴(yán)重 這樣保證整個(gè)傾斜煤層巷 道的穩(wěn)定性的關(guān)鍵就是保證邊墻的堅(jiān)實(shí)和完整 2 巷道周圍的松動區(qū)域的測量巷道周圍的松動區(qū)域的測量 基于松動區(qū)域的挖掘理論 一個(gè)松動區(qū)域通常在挖掘的洞的周圍形成 因?yàn)?那的應(yīng)力比初應(yīng)力低 由于傾斜煤層巷道的不規(guī)則形狀和各向異性的媒介 在巷 道周圍的松動區(qū)域也是不規(guī)則的形狀 我們使用一種超聲波裂縫探測儀 撫順煤 炭科學(xué)和技術(shù)學(xué)院研發(fā)的型號為 sc ii 來測量巷道的松動區(qū)域 測試結(jié)果如圖 3 所示 巷道被兩個(gè)到頂?shù)?1 6 米的錨噴支護(hù)支撐 錨噴支護(hù)內(nèi)有一點(diǎn)混凝土預(yù) 應(yīng)力 被測量的松動區(qū)域是上方邊墻煤層高 1 8 米 下方邊墻煤層低 1 4 到 1 5 米 并且頂?shù)母叨仁?0 95 到 1 1 米 本科畢業(yè)設(shè)計(jì) 論文 通過答辯 圖 3 傾斜煤層巷道周圍松動區(qū)域的結(jié)果 巷道在沒有開采影響下可以是穩(wěn)定的 但是只要受到開采的影響 巷道將會 由于邊墻的失效和頂?shù)牡袈涠顾?在最終的情況下 最大的采礦高度可以達(dá)到 4 0 米 因此傾斜煤層的巷道很難維護(hù) 而且維護(hù)費(fèi)用非常高 測試的結(jié)果是符合數(shù) 值計(jì)算的 所以加固包括邊墻在內(nèi)的巷道是非常必要的 3 錨桿頂?shù)膬A斜組合橫梁的模型錨桿頂?shù)膬A斜組合橫梁的模型 在傾斜煤層中 當(dāng)錨桿的長度小于軟且松動的頂時(shí) 錨桿頂將傾斜的頂聯(lián)合 起來 當(dāng)然如果錨桿可以支撐到一個(gè)合適的地層 那么錨桿裝置將會掛在上面 一種典型的傾斜組合橫梁模型如圖 4 所示 橫梁是由幾個(gè) 層的總數(shù)為 k 不同 性質(zhì)的長度為 l 且厚度 為地層組成的 有如下假設(shè) 1 每一層的橫梁是均勻 的 連續(xù)的 各向同性的 2 橫梁屈服于小的變形 3 每一層同時(shí)變形 且 沒有在基面上的滑動 圖 4 傾斜組合橫梁的錨桿頂模型 按照橫梁的標(biāo)準(zhǔn)強(qiáng)度 組合橫梁最小的厚度 可以被得出 并且錨桿的 總長度可以被容易的確定如下 2 1 l l l 1 這里 1 l 是錨桿的長度 2 l 是伸出部分的長度 由錨桿不會沿著基床滑動的規(guī)律 錨桿間距 a 可以得出 除了以上提到的條 本科畢業(yè)設(shè)計(jì) 論文 通過答辯 件 組合橫梁的安全性一定要被檢查 以保證它的縱向的穩(wěn)定性 當(dāng)所有的條件都具備了 錨桿頂參數(shù)就可以被確定了 至于邊墻的錨桿 它 們的長度和間距可以由巖土力學(xué)中的巖土支撐理論得出 當(dāng)頂是由不牢固和松軟的地層構(gòu)成時(shí) 一定要實(shí)施一些支撐的措施 來保護(hù) 易碎頂?shù)耐暾?4 巷道的錨桿支護(hù)及其評定巷道的錨桿支護(hù)及其評定 4 1 離散元素法的支撐評定離散元素法的支撐評定 我們考慮到兩種情形來比較 一種是只有頂被錨桿支護(hù) 另一種是頂和邊墻 都被支護(hù) 使用第一種情形的支