朱集煤礦0.9Mta新井設(shè)計含5張CAD圖-采礦工程.zip,煤礦,0.9,Mta,設(shè)計,CAD,采礦工程 英語原文 Optimization of soft rock engineering with particular reference to coal mining qiuyan Fan Abstract Soft rock engineering is a difficult topic which has received much attention in the field of rock mechanics and engineering. Research and practical work have been carried out, but much of the work has been limited to solving problems from the surface. For overcoming the difficulties of large deformations, long duration time-dependent effects, and difficulties in stabilizing the soft rock, the problem should be tackled more radically, leading to a more effective method of achieving optimization of the engineering system in soft rock. A summary of the optimization procedure is made based on engineering practice. 1. Introduction There are many soft rock engineering problems around the world, involving engineering for mines, highways, railways, bridges, tunnels, civil subways, buildings, etc. Engineering losses have occurred because of volumetric expansion, loss of stability of the soft rock, etc. This has been an important question to which much attention has been paid in engineering circles, and in the field of academic rock mechanics. Since the 1970s, considerable research and practical efforts have been made in the field of soft rock engineering in various countries, but the major efforts were concentrated on such aspects as the method of construction, the design and reinforcing of the supporting structures, measurement and analysis of the rock’s physical and mechanical properties, its constitutive relations and engineering measurement. It has been found that the soft rock engineering problem involves complex systematic engineering including such subsystems as classification of soft rocks, judgement concerning the properties of soft rock, project design and construction. Only by considering the integral optimization of the system can we obtain an improved solution to the problem. Hopefully, a radical approach can lead to engineering feasibility, lower costs and engineering stability in order to achieve the engineering objectives. 1.1. Mechanical properties of soft rock and associated engineering Soft rock is an uneven and discontinuous medium. Its strength is low, with a uniaxial compressive strength usually lower than 30 MPa. Some soft rocks expand when they are wet. Cracks in some soft rocks will propagate easily — which makes them exhibit volumetric expansion. Large deformation and creep can occur in soft rocks. Many soft rocks are compound ones which have composite properties formed from two or more sets of constituent properties. Soft rock can be graded into divisions according to its properties. After engineering has occurred, soft rock can deform rapidly and by time-dependent deformation, owing to its low strength and sensitivity to the stress field. With the effect of water, the expansive minerals in soft rocks volumetrically expand, which causes large convergent deformations, which leads to damage of the surrounding rock. The mechanical properties of soft rocks appear so various and different that it is difficult to express them with mathematical formula, which is the technological challenge for soft rock engineering. 1.2. Engineering in soft rock and its optimization Because soft rock engineering can induce large deformations, the maintenance of the engineering can be difficult. Moreover, volumetric expansion and loss of stabilization of the surrounding rock often causes damage to supporting structures. If we use strong supports to control the deformation of the surrounding rock, the engineering cost will be high, and the construction time will be increased by repeated installation of support, sometimes the support itself has to be repaired. In order to obtain the benefits of easier construction and lower cost, the integral optimization of the system must be carried out and managed in a systematic and comprehensive way. Design and construction are the two important steps in soft rock engineering. These must begin by understanding the physical and mechanical properties of soft rock, in the context of the stress field, hydrogeology and engineering geology. The engineering design plan is conceived as a whole according to the theory of rock mechanics and combining practical data from adjacent or similar projects, including integrating the many factors. The establishment of the correct soft rock engineering system should come from practice, basing on a full mastery of the factors. Optimization of soft rock engineering is achieved by making the surrounding rock interface with the supporting structure such that the engineering will be stable. The key technological strategy is to avoid a high stress field and enhance the supporting ability of the surrounding rock. Feasible measures are as follows: reducing the external load; optimizing the engineering structure’s size and shape, improving planar and cubic layouts of engineering; choosing better strata, and structure orientation, etc. According to these ideas, take the development of a coal mine in soft rock as an example. Integrated optimization of the development system of the mine should take the relevant factors into account: existing information; an overall arrangement for optimal development and production; eliminate adverse factors; and deal with the problems of soft rock by a simple construction method. The content of the first part of the optimization includes: choosing the mine development method; deciding on the mining level; and determining layers in which the main roadways are to be located. Also important is arranging a reasonable layout of the pit bottom and chamber groups and seeking to reduce the deviator stress caused by mutual interference of the openings. Openings perpendicular to the direction of horizontal principal stress should be avoided when choosing the driving direction of roadways. Optimizing the layout of the mining roadways reduces the damage to support caused by moving loads introduced by mining. Further optimization is related to the geometry and size of the roadway sections, the supporting structure, and the method and technology of construction. Finally, by measuring and monitoring during construction, feedback information can be obtained to ensure that the engineering is running on the expected track and, if there is any deviation, corrective action can be implemented. 2. Engineering examples 2.1. Mine No. 5 in Youjiang coal mine, China The mine is situated to the east of Baise Coalfield, in the West of Guangxi Zhuang Autonomous Region. It belongs to the new third Period. The mine area is located at the edge of the south synclinal basin. There are three coal layers; the average thickness of each seam is 1–2?m; above and below the coal layers are mudstone, whose colours are grey, greyish white, and green. There are minerals of mixed illite and montmorillonite in the rock, montmorillonite 5–8%, and illite 7–20%. The rock’s uniaxial compressive strength is 4–5 MPa, the average being 4.8 MPa. There are irregular joints in the rock, but distributed irregularly, and the rock’s integral coefficient index is 0.55. Most of the cracks are discontinuous, without filling matter in them. The surrounding rock is a soft rock subject to swelling, with low strength, and is quite broken. The strike of the coalfield is NEE, the dip angle of the coal layers is 10–15°. The mine area is 6?km long along the strike, and 1?km long along its inclination, its area is 6?km2, the recoverable reserves are 4,430,000 tons. In the adjacent mine No. 4, the maximum principal stress is NNE–SSW, approximately along the seams’ inclined direction. A roadway perpendicular to this direction has convergence values of 70–100?mm, the damage of roadway supports is 51%. A roadway parallel to the direction of maximum principal stress has convergence values of 20–40?mm, the damage rate of supports is 12%, and the average damage rate of the mine is 40%. In the design of the mine, a pair of inclined shafts were included. The level of the shaft-top is +110?m, the elevation of the main mining level is located at ?120?m. Strike longwall mining is planned, arranging with uphill and downhill stope areas, as shown in Fig. 1. Fig. 1. Development plans for Mine No. 5 in Youjiang. The first optimization measure is to weaken the strain effect of the surrounding rock in the mine roadway caused by the stress field. Roadways are arranged as far as possible to be parallel with the maximum principal stress (that is, approximately along the inclined direction) so as to reduce the angle between them. The strike longwall mining is changed into inclined longwall mining, the mine is mined upward by using the downhill stope area, the main mining level is elevated by 20?m, 1131?m of roadways are saved and the cost of the roadway construction and facilities is saved ￥2,760,000 ($336,600). The new system is shown in Fig.2. Fig. 2. Development system plans after optimization for Mine No. 5 in Youjiang. The second optimization measure is to change the layout of the pit bottom and openings to be parallel with the maximum principal stress as far as possible. The total length of roadways initially designed was 1481?m, and 30.11% of them were arranged to be perpendicular to the maximum principal stress. After amendment, the total length of roadways is 1191?m, which is a decrease of 290?m, and with only 24.69% of roadways that are perpendicular to the principal horizontal stress, roadways are easier to maintain. The third optimization measure is to excavate the section of the roadway in a circular arch shape to reduce the stress concentrations. In order to increase the supporting ability of the surrounding rock itself, after the roadway has been excavated, rockbolts are installed as the first support. Considering the expansivity of the surrounding rock, guniting is not suitable. The secondary support is the use of precast concrete blocks. Between the support and the surrounding rock, the gaps should be filled with a pliable layer of mixed lime-powder with sand. This produces the effect of distributing the stress and has a cushioning effect when the soft rock is deforming; also, it inhibits the soft rock from absorbing water and expanding. This scheme is shown in Fig. 3. Fig. 3. Optimization design for the supporting structure of the main roadway for Mine No. 5 in Youjiang. The fourth optimization measure is to simplify the chamber layout so as to reduce the number of roadways. For example, in order to decrease the stress concentrations by the roadway, the number of passageways in the pumproom and the sub-station can be reduced from three to one, and the roadway intersections connecting at right-angles can be reduced from 14 to nine. The fifth optimization measure is in accordance with the different stratigraphical lithologies which the roadways pass through, and for harder rock regions to change the roadway section into a structure with straight-sided semicircular top arch and arc bottom arch, and another structure with a straight-sided horse-shoe arch, so that the investment of supporting structure can be saved when there are better rock masses with comparatively few fractures. In construction, waterproofing and draining off the water should be implemented, and the catchment in the roadway bottom should be strictly prevented because it may cause the bottom rock to expand. When the opening groups are excavated, the construction sequence must be considered, enough rock pillar must be reserved, and the construction method of ‘short-digging and short-building’ must not be used, so that the interactions can be avoided. By the optimization described above, after the roadways have been constructed, the serviceable roadway is 95.5% of the total, 55.5% more than that of the adjacent mine No. 4. The length of the roadway was reduced, and ￥3,700,000 ($450,000) saved. In addition, ￥3,000,000 ($360,000) was saved in the maintenance costs of the roadways before the mine was put into production, so, the cost saving totals ￥6,700,000 ($810,000) in all. After the mine has been turned over to production, the main designed capacity was reached in that year, and added to the saved money for the maintenance cost of roadways in production, there was ￥8,700,000 ($1,050,000) saved. 2.2. The coal mine at Renziping, China The mine lies to the south of Qinzhou coalfield in Guangxi Zhuang Autonomous Region. It belongs to the new third Period and synclinal coal basin tectonics. There are two coal layers in it, the main seam thickness is 12–15?m. The roof and floor of the coal layers are arenaceous–argillaceous rocks, whose colour is greyish white, and whose essential minerals are quartz and kaolinite. The uniaxial compressive strength of the rock is from 10 to 15 MPa. Rock masses are quite integral with fractures only in it occasionally. It belongs to the class of soft rock that has weak expansion, lower strength, and is quite broken. There are faults around the coalfield basin which are 8?km long and 1.5?km or so wide. Slopes are inconsistent, the edge angles are 25–40°, and the bottom of the coalfield is gentle. Affected by tectonic stress in the NW–SE direction, there is an inverse fault in the south. After the mine had been developed and put into production, a main roadway at the 250?m level was excavated along the strike, and the mine was mined by the ‘uphill and downhill stope area’. Affected by the rock stress, many parts of the main roadway have ruptured, parts have been pressed out, and supports have been broken; the serviceable rate of roadway supports was less than 40%, which seriously affected the haulage and ventilation of the mine road. In the following 10 years of production, the rated production output was not achieved and losses occurred leading to economic disbenefit. Through on-the-spot observations, it is apparent that the coalfield is affected by the tectonic stress field, that the deformation in the soft rock is serious, and is larger than that caused only by the vertical stress component. The technological reformation measures for the mine are proposed as follows. The first measure is to extend the depth of the shaft and abandon the main roadway excavated along the strike, and transform it into a bottom panel stonedoor along the synclinal basin minor axis to make it parallel with the main principal horizontal stress. The mining face can be laid on top of it. The force endured by the stonedoor is quite small, and the stonedoor is easy to maintain, as shown in Fig. 4. Fig. 4. Contrasting layouts before and after optimization at the coal mine in Renziping. The second measure is to select an improved stratum to lay out the stonedoor. If it is placed in the grey arenaceous–argillaceous rock, its uniaxial compressive strength is 15 MPa and is easy to maintain, constructing in the normal excavation manner, and supported with a granite block building body. After the mine was constructed, the maintenance of the stonedoor was in a better state, the serviceability rate of the roadway was raised to 85%, which is 45% more than that before the optimization. The haulage and ventilation of the mine were also improved, to enhance the normal production. The coal production of the mine has surpassed the designed capacity, the loss has been reversed and the mine has been transformed to a profitable enterprise. 3. Conclusions Soft rock engineering for coal mining involves many complex factors. Unable to solve the problems completely by quantitative means, much of the engineering relies on feedback after observation on the spot. The technique described in the paper — of systematic decomposition of the system into the component elements, individual optimization and then synthesis into overall optimization — has achieved good results in practice, as illustrated by the two coal mine examples. In fact, the basis of the technique is the process of applying basic rock mechanics principles, such as orienting roadway tunnels to be parallel to the maximum horizontal principal stress and avoiding complex excavation shapes. This involves major changes to coal mine layouts and thus represents a strategy of taking radical measures to solve soft rock engineering problems. If such radical measures are taken together with holding stopgap measures, the soft rock engineering can be optimized. 中文譯文 煤礦開采中的軟巖優(yōu)化工程 范秋雁 摘要 軟巖工程是一個困難的課題，已受到巖石力學(xué)與工程領(lǐng)域的廣泛關(guān)注。研究和實際工作已經(jīng)開展，但工作一直局限于解決表面問題。對于大變形，持續(xù)時間長的效應(yīng)，必須解決軟巖穩(wěn)定性的難題，為了問題更徹底的解決，應(yīng)該形成一個更有效的軟巖工程優(yōu)化系統(tǒng)的方法。本文簡要介紹工程實踐基礎(chǔ)上的軟巖優(yōu)化過程。 1.前言 在世界各地有不少軟巖工程問題,涉及礦山,公路,鐵路,橋梁,隧道, 民用地鐵，建筑等工程損失已經(jīng)發(fā)生。因為軟巖體積膨脹,失去穩(wěn)定性而引發(fā)的，這是一個巖石力學(xué)領(lǐng)域一直非常重視的問題。自20世紀(jì)70年代以來，各個國家在軟巖工程領(lǐng)域投入了大量的研究和實踐，但主要精力都集中在設(shè)計和加固支撐結(jié)構(gòu)，測量和分析巖石的物理力學(xué)性能指標(biāo)，工程施工方法與巖石結(jié)構(gòu)關(guān)系等方面。 在已經(jīng)發(fā)現(xiàn)的軟巖工程問題中,涉及到復(fù)雜的系統(tǒng)工程包括軟巖系統(tǒng)分類,軟巖工程設(shè)計與施工。 只有考慮到整體系統(tǒng)的優(yōu)化,才能取得更好的解決辦法。一個優(yōu)化的方式,可以降低工程成本，提高工程穩(wěn)定性,以實現(xiàn)工程目標(biāo)。 1.1.軟巖力學(xué)性質(zhì)及相關(guān)工程 軟巖是一個不平衡的連續(xù)介質(zhì)。其強度低,單軸抗壓強度通常低于30 MPa。 有些軟巖濕度增加時體積擴大。在一些軟巖中裂縫較發(fā)育,導(dǎo)致巖石體積膨脹，發(fā)生大變形和蠕變。 許多軟巖是由兩種或多種不同巖性巖石組成的復(fù)合型軟巖,可依據(jù)巖石性能劃分等級。 由于軟巖強度低，應(yīng)力場靈敏度高，礦物質(zhì)遇水膨脹后，軟巖體積擴大，能迅速產(chǎn)生大的收斂變形和時效變形, 導(dǎo)致圍巖的破害。 從軟巖的力學(xué)性能來看，用數(shù)學(xué)公式精確描述其眾多性能參數(shù)的變化規(guī)律，是軟巖工程技術(shù)上的極大的挑戰(zhàn)。 1.2. 軟巖工程及其優(yōu)化 在軟巖中進行施工,能促使巖體產(chǎn)生大變形,維修的工程也很困難。 此外,巖石體積膨脹，往往造成巖體支撐結(jié)構(gòu)損壞，圍巖喪失穩(wěn)定性。如果采用強力支撐, 以控制變形的圍巖，將增加建造時間，提高工程成本, 有時支撐系統(tǒng)本身已經(jīng)得到修復(fù)，而形成重復(fù)支撐。 為了簡化施工,降低成本，從而獲得最大效益,必須全面地、有系統(tǒng)地進行優(yōu)化。 在軟巖工程的設(shè)計與施工中必須了解軟巖的物理和力學(xué)性能，及圍巖應(yīng)力場,水文地質(zhì)與工程地質(zhì)條件。工程設(shè)計方案是根據(jù)相鄰或相近巖石力學(xué)數(shù)據(jù)與實踐相結(jié)合，整合多種因素，產(chǎn)生的一個整體的構(gòu)想。正確的軟巖工程系統(tǒng)建立在實踐中掌握的各種因素之上 。 軟巖優(yōu)化工程是通過支護結(jié)構(gòu)改變圍巖性質(zhì)，使工程趨于穩(wěn)定。其關(guān)鍵技術(shù)，是避免高應(yīng)力場和提高圍巖的支撐能力?？尚械拇胧┤缦?減少外部荷載;優(yōu)化工程的結(jié)構(gòu)大小和形狀,加強工程平面和立體布置，選擇具有更好結(jié)構(gòu)和方向的地層等 。 根據(jù)上述思路，以一個在軟巖地質(zhì)條件下的生產(chǎn)煤礦為例。對礦井進行發(fā)展系統(tǒng)的綜合優(yōu)化，應(yīng)考慮相關(guān)的因素:實際情況；最佳的開發(fā)和生產(chǎn)計劃；消除不利因素；用簡單的方法處理軟巖問題。設(shè)計第一部分的優(yōu)化包括:選擇礦山開拓方式；劃分開采水平；并確定主要運輸系統(tǒng)的位置。同樣重要的是合理的安排巷道和硐室的位置，設(shè)法減少工程之間造成的相互干擾。水平主應(yīng)力的開口垂直方向應(yīng)避開運輸路線?；夭上锏赖牟贾脩?yīng)減少開采引起的移動荷載所造成的支持結(jié)構(gòu)的損傷。進一步優(yōu)化因涉及到線路的幾何形狀、尺寸大小、支承結(jié)構(gòu)及施工工藝和方法。最后，通過測量和施工監(jiān)控，及時反饋信息，確保工程按預(yù)定的計劃進行，如果有任何偏差，可及時采取糾正措施。 2.工程實例 2.1.中國右江五號煤礦 煤礦坐落于廣西壯族自治區(qū)百色煤田東部。屬于三疊紀(jì)。 礦區(qū)位于南向斜盆地的邊緣。 有3層煤; 各煤層平均厚度1-2米; 煤層頂?shù)装寰鶠槟鄮r,其顏色是灰色,灰白色,綠等。巖石中混合蒙脫石和伊利石,蒙脫石占5-8%,伊利石占7-20%。 巖石的單軸抗壓強度是4-5 MPa,平均為4.8 MPa。巖石裂隙較發(fā)育,且不分布規(guī)則,。巖心質(zhì)量指標(biāo)是0.55 。 大部分的裂縫之間無膠結(jié)物填充。 圍巖受流水侵蝕,強度降低,完全破碎。煤田走向延伸,傾角煤層是10-15 °， 礦區(qū)走向長6公里的, 傾向約1公里，面積為6平方公里,可采儲量是4,430,000噸。 在相鄰四號礦井,最大主應(yīng)力為北北東-南南西,大致沿煤層的傾斜方向。 巷道垂直于這個方向的收斂值70-100毫米,巷道支護破壞程度是51% 。巷道平行于最大主應(yīng)力的收斂值為20-40毫米, 支護損壞程度是12% , 煤礦平均支護損壞程度為40%。 在礦井的設(shè)計中,考慮一對斜井開拓。水平軸頂部是110米,主要開采水平設(shè)在-120米。走向長壁上下山開采,如圖1 。 圖1 右江五號煤礦發(fā)展計劃 第一優(yōu)化措施是為了削弱巷道所受到的圍巖應(yīng)力應(yīng)變的影響。巷道盡可能平行與最大主應(yīng)力(即大致沿傾斜方向)，減少夾角。走向長壁開采改為傾斜長壁開采，煤礦開采是使用下山開采，主采水平提高了20米,少掘巷道1131米，減少了掘進費用，以及設(shè)施費用,節(jié)?。?,760,000(33.66萬美元)。新系統(tǒng)是見圖2。 圖2 系統(tǒng)優(yōu)化后右江5號煤礦發(fā)展計劃 第二項優(yōu)化措施，改變井底硐室布局方式，盡量作到簡潔，硐室的開口應(yīng)平行于最大主應(yīng)力方向。最初設(shè)計總長度是1481米，其中30.11%垂直于最大主應(yīng)力。修改后的巷道總長度是1191米，即減少了290米，只有24.69 %的巷道垂直于主水平應(yīng)力，巷道容易維護。 第三優(yōu)化措施是采用圓拱形狀井筒斷面，以減少應(yīng)力集中。井筒開鑿后，為了提高圍巖本身的支撐能力，采用錨桿及時支護?？紤]圍巖的膨脹性，噴射混凝土并不適合。二次支護采用澆注混凝土?；炷梁蛧鷰r之間采用石灰粉混合砂土填充。這就產(chǎn)生了分散壓力的效果，圍巖變形時起到緩沖作用, 同時,它抑制軟巖吸水膨脹。計劃見圖 3。 圖3 右江5號煤礦主要巷道支撐結(jié)構(gòu)的優(yōu)化設(shè)計 第四優(yōu)化措施，是為了簡化井下硐室布置，以縮短線路。比如,為了減少硐室產(chǎn)生的應(yīng)力集中，水泵房及變電所，可以從三個減少到一個，巷道交叉口的連接數(shù)，可以從14個下降到9個。 第五優(yōu)化措施，按照巷道通過的不同地層的巖性，在通過困難地區(qū)改變巷道斷面形狀改成一個結(jié)構(gòu)簡單的半圓拱形或另一種結(jié)構(gòu)簡單的馬蹄型拱，可以減少巷道周圍巖體相對折斷，從而節(jié)省對支撐設(shè)備的投資。 在硐室及巷道，應(yīng)實施防水及排水措施，嚴(yán)格禁止硐室以及巷道底部集水，因為它可能導(dǎo)致底部巖石膨脹變形。當(dāng)確定開鑿的施工順序后，必須考慮保留有足夠的巖柱；不得采用的短挖短建的施工方法，以避免相互作用。 通過優(yōu)化設(shè)計，已建成的巷道中95.5%可較好的使用，其中 55.5%以上的巷道使用期大于相鄰四號礦井。減少了巷道長度,節(jié)?。?3,700,000 ( $ 450,000 )。此外，礦井投產(chǎn)前巷道維修費用節(jié)省了￥ 3,000,000(360,000元)，所以 節(jié)約成本總計￥ 6,700,000 ( $ 810,000)。煤礦投入生產(chǎn)后，當(dāng)年達產(chǎn)，加上節(jié)省下來的巷道生產(chǎn)期間維修費用，共有￥ 8,700,000 ( $ 1,050,000 )。 2.2. 中國稔子坪煤礦 煤礦位于廣西壯族自治區(qū)欽州南部，它屬于第三紀(jì)向斜盆地構(gòu)造。含兩個煤層,其主要煤層厚度為12-15米。煤層的頂?shù)装鍨樯澳噘|(zhì)巖，其顏色是灰白色，其主要礦物是石英和高嶺石。單軸抗壓強度從10- 15 Mpa。巖體相對完整只有部分地區(qū)較破碎。屬于軟弱圍巖，軟膨脹，強度較低，是易破碎。煤田盆地附近有約8公里長，1.5公里范圍的斷層。斜坡上變化較大，邊角度25-40°。煤田的底部較為平緩。受構(gòu)造應(yīng)力影響，在煤田南部有一個NW-SE方向逆斷層。煤礦已開發(fā)并投入生產(chǎn)后, 礦山采用上下山開采,250米主運巷道沿走向延伸。受巖石應(yīng)力應(yīng)力影響,許多地方的主要巷道已經(jīng)破裂,支護被打破，部分已壓出,巷道的可用率小于40%，這嚴(yán)重影響了煤礦的運輸與通風(fēng)。在經(jīng)過10多年的生產(chǎn), 沒有達到額定產(chǎn)量且有虧損情況發(fā)生，導(dǎo)致經(jīng)濟損失。 通過現(xiàn)場觀察，該煤田受構(gòu)造應(yīng)力場影響明顯，垂直應(yīng)力分量造成軟巖嚴(yán)重變形，為礦井提出的技術(shù)改造措施建議如下： 第一項措施是將增加深度的豎井，放棄沿走向布置的主要巷道，采用平行向斜盆地短軸的巷道，其主要受橫向壓力。采煤工作面,可以布置在巷道之上。巷道經(jīng)受的巖石壓力很小，且巷道易于維護,如圖4。 圖4 煤礦布局優(yōu)化前后的對比 第二招則是將石門置于良好的地層。如果我們把它放置于單軸抗壓強度為15 MPa灰色砂質(zhì)泥巖中, 以正常的施工方式建設(shè),并用花崗石做支護，將有利于維護。 礦井經(jīng)過優(yōu)化建設(shè),維修后的石門處于一個較好的狀態(tài),巷道的服務(wù)