关 键 词：

专题冲击矿压及其预防控制 含CAD图纸+文档 煤矿 1.2 Mta 设计 专题 冲击 及其 预防 控制 CAD 图纸 文档

资源描述：

压缩包内含有CAD图纸和说明书,均可直接下载获得文件，所见所得，电脑查看更方便。Q 197216396 或 11970985

内容简介：

专题部分 第35页冲击矿压及其预防控制1 冲击矿压成因冲击矿压的成因好机理的研究内容包括三方面：分析冲击矿压发生的基本条件和影响因素；探讨冲击矿压发生的原因和规律；研究冲击矿压的孕育、发生、发展和停止的物理过程。研究的目的在于深入了解这种现象的本质，掌握它的活动规律，为预测和治理提供理论基础，搞好冲击矿压防治。1.1弹性变形能冲击矿压的巨大破坏性在于煤岩体瞬间释放出大量的能量。从能量转化的角度来看，冲击矿压的孕育和发生过程就是能量的积聚和突然释放的过程。为了说明冲击矿压这种现象，首先必须搞清弹性变形能的概念。地下岩体（包括煤体）是处于复杂的和强大的自然应力、构造应力和开采附加应力场中。这样，地下赋存的岩层和煤层在强大的应力总用力，必然导致其体积与形状发生变化，即产生变形。这种变形是外力做功的结果。当岩快尚处于弹性状态，且变形不能解除时，外力做的功将以能量的形式储存在岩体中。这种由变形获得的能量称为弹性变性能，也称为弹性位能，或简称为弹性能。因此，处于三向高应力状态下的地下岩体，可能储存有大量的弹性能。由于在外力作用下岩体发生体积和形状变化。一旦积聚的弹性能与应力大小及煤岩体的力学性质有关。1.2冲击倾向煤层冲击是冲击矿压的最常见的显示形式。因此煤的冲击倾向是冲击矿压机理研究的重要内容之一。大量的冲击矿压实例表明，同一矿井，在几乎相同的自然地质和开采技术条件下，有些煤层发生冲击矿压，有些则不发生。这就说明发生冲击矿压的煤体一般都具有一定的物理力学特性，决定其积聚能量并产生破坏的能力。这种能力可称之为冲击倾向，是煤的固有属性。煤层冲击倾向鉴定是进行预测和治理的前提，也是管理工作的基础。在地质勘探阶段，从勘探钻孔取得煤心，在实验室进行煤的冲击倾向鉴定，其结果可作为矿井设计的基础技术依据，以便从开采程序及方法、开拓布置上采取措施，从根本上消除冲击矿压的发生条件；在煤层开采以后，通过进一步的冲击倾向鉴定工作，确定待采区的冲击倾向性级别，为生产、管理工作提供客观的基础技术依据。1.2.1煤样动态破坏时间在常规单轴压缩试验条件下，煤试件从极限强度到完全破坏所经历的瞬态延续时间称为煤样动态破坏时间，冲击矿压之所以成为一种灾害，不仅在于媒体破坏释放出的能量非常大，而且在于煤体冲击破坏的过程短暂。显然，破坏过程的长短是能量积聚与耗散动态特征的综合反映。因此，煤样的动态破坏时间可以衡量冲击倾向性的程度。在一定条件下，煤样的破坏时间取决于断裂发展的速度。对岩块断裂机理的研究表明，岩石（包括煤）在压缩下的脆性破裂分为三个阶段：1、从断裂开始出现到临界能量释放点，属断裂稳定扩展阶段，断裂速度从零开始增大；2、从临界能量释放点到极限强度，属断裂不稳定扩展阶段，断裂速度继续增大并渐近于极限值，对于给定的介质，极限值为常值；3、从极限强度到试件完全崩裂，属断裂的分叉与汇合阶段，在普通试验机加载条件下，这一过程是在极高的速度下完成的。上述分析证明，在普通试验机加载条件下，脆性煤块的破坏时间取决于断裂分叉与汇合的速度，它反映了煤介质的固有属性。试验方法与常规单轴抗压强度试验相同。在普通压力试验机上，以加载速率控制方式对煤试件加载。加载速率取恒定值，约0.51.0MPa/s。利用载荷传感器把试件所受的力变为电压信号，再经动态应变仪放大后，输入模拟磁带机，进行连续记录至试件破坏。然后，用记忆示波器捕捉磁带机回放过程中载荷信号的跌落过程。最后，测量载荷从峰值跌落到零的延续时间，并用X-Y函数记录仪绘制破坏过程中的载荷-时间曲线，便得到测量结果。强烈冲击倾向的煤，断裂扩展异常迅速，试件急速丧失承载能力，中等冲击倾向的煤，结构失效和材料失效的阶段分界比较明显，试件首先经历较慢的承载能力降低的过程，以后才很快失去抵抗的能力；无冲击倾向的煤，断裂扩展比较缓慢，承载能力的降低呈现多次台阶式的发展过程，残余强度表现明显。试验表明，所测11种煤样的动态破坏时间Dt服从以下鉴定判据：Dt=50ms 冲击倾向强烈50Dt500ms 无冲击倾向Dt作为煤的冲击倾向鉴别指标具有以下优点：1、综合反映了煤在加载系统作用下能量变换的全过程，突出表现了煤的破坏动态特征；2、在一定范围内，在不受加载速度、试验机刚度和式样强度的影响，反映了煤的固有冲击倾向属性；3、对冲击倾向敏感，冲击倾向不同的煤，其Dt有量级差别，便于分级；4、试验方法简单，便于采用先进的量测系统。1.2.2弹性能指数WET弹性能指数WET是单位体积的煤破坏前在受力过程中所储存的弹性变形能与消耗的能量的比值。显然，煤受力后所消耗的能量越少，而储存的能量越多，它发生冲击矿压的可能性 越大。因此，弹性能指数的大小反映了煤层的冲击倾向性。根据大量的实验结果，按WET对煤层冲击倾向进行鉴别的指标如下：WET=5 煤层具有强烈冲击倾向2WET=5 煤层具有较弱冲击倾向WET1)来表示，则破碎煤块单位体积所需的能量U2为UV= KRC2/2E按冲击矿压能量准则有UV= U2由此得K0C2H2/6E= K0RC2/2E化简得H=1.73K0CRC/释放出来的能量为U=UV- U2=C2H2-3 K0RC26E式中还不能做定量计算使用，因为对具体矿井来说，实际条件是复杂的。两式只说明达到一定开采深度是形成冲击矿压的一个基本条件。国内外实际资料也证明，多数矿井的开采深度达到200m以上，才会发生冲击矿压，见表7-3和表7-4所列；此外还说明冲击矿压发生的频度和强度都随着深度的增加而增加，见表7-5、表7-6所列。表7-3我国部分矿井发生冲击矿压的初始深度局、矿名称门头沟天池抚顺、大同城子矿大台矿陶庄矿房山矿唐山矿初始深度/m200240250300330460480520540表7-4国外矿井发生冲击矿压的初始深度国别南非美国加拿大俄罗斯波兰德国英国初始深度/m120300150180180400240300600表7-5发生冲击矿压的强度和频度与开采深度的关系地区与矿名强度或频度单位开采深度201300301400401500501600601700重庆地区发生强度t/次681189471250天池矿发生次数次13996%3.511.5323222统计分析表明,开采深度越大,冲击矿压发生的可能性也越大。当深度H350 m时,冲击矿压一般不会发生; 350 m =3.1共六级。这种分类法能直接反映震源释放的冲击能量大小，数据较明显、客观，便于统计。根据冲击矿压的破坏后果，可分为三类： 冲击矿压事故由于冲击矿压及其伴随现象（冒顶、瓦斯突出等），造成的人员伤亡事故，或者由于井巷或采场破坏造成中断工作8h以上。发生冲击矿压事故，除填报记录卡以外，还要写出事故调查，报告上级。 破坏性冲击矿压造成一定的生产破坏，需进行修复工作的冲击矿压。发生破坏性冲击矿压后应填报记录卡。 一般冲击矿压仅出现震动和声响，同时可能伴随粉尘飞扬，但不出现煤（岩）冲出或散落在巷道中的现象。一般冲击矿压对生产的破坏后果轻微，不需要进行修复，对一般冲击矿压应有记录并逐月填报统计表。五、防治内容防治内容视防治区域级别不同而有所侧重，这样才能符合实际情况，取得更好的技术经济效果。划分待采区域防治级别的工作，应根据冲击倾向鉴定结果，采用经验类比法对生产地质条件进行分析，一般应着重考虑以下因素：(1) 本煤层本区已发生冲击矿压，本煤层相似条件下的采区以发生冲击矿压；(2) 煤层的冲击倾向程度；(3) 煤层老顶厚为5m以上，强度大于70MPa的坚硬岩层；(4) 孤岛形煤柱；(5) 上方100m以内有回采边界；(6) 煤层厚度和倾角有突然变化（在10m长度内变化率大于20%）；(7) 地质构造带，向斜轴部，断层附近。在以上综合防治方案中，根据对上述因素的分析，将待采区划分为重点防治区、一般防治区与常规防治区。当然，也可划分成两级或四级。应注意防治区的级别是可变的。在采空面积加大的情况下，低级防治区可升为重点防治区；在采取治理措施并经检查有效时，重点区也可降低。在实际工作中应及时作相应的改变。六、科学研究在冲击矿压综合防治过程中，应自始至终对冲击矿压机理和规律进行研究。首先，在划分防治区域级别时，要进行煤岩物理力学性能特别是煤层冲击倾向的试验，同时要分析生产地质条件中其他各种因素对本地区冲击矿压的影响。进行影响因素分析时，要特别注意引起冲击矿压的应力主要是开采支承压力，还是地质构造应力，或者是多种因素的综合作用。其次，要组织一定的科研力量，采取多种手段，进行本地区支承压力和构造应力分布规律、弹性能积聚和释放过程的时空汇率研究。在此基础上，进行预测预报的科学试验，得出适合于具体生产地质条件下的冲击危险判据。同时，要进行各种改变煤岩结构和力学特性以及控制弹性能释放过程的各种方法的试验和实施，即治理措施的实施方法的试验研究、工艺参数的合理选择和施工设备的选型。参考文献1乔长君.变配电线路安装技术手册.化学工业出版社20102方文,蔡晶,张季超等.如何搞好工程项目施工质量控制.建筑技术开发,20033陈汉民. 关于消防用电设备配电线路的讨论J. 建筑电气,2009,.4 窦林名, 何学秋. 冲击矿压防治理论与技术M. 徐州:中国矿业大学出版社, 2001.5 窦林名, 赵从国, 杨思光, 等. 煤矿开采冲击矿压灾害防治M. 徐州: 中国矿业大学出版社, 2006.6 李世愚, 和雪松, 张天中, 等. 地震学在减轻矿山地质灾害中的应用进展J. 国际地震动态, 20067 李庶林, 尹贤刚, 王泳嘉, 等. 单轴受压岩石破坏全过程声发射特征研究J. 岩石力学与工程学报, 2004,8 陈忠辉, 傅宇方, 唐春安. 岩石破裂声发射过程的围压效应J. 岩石力学与工程学报, 19979 张茹, 谢和平, 刘建峰, 等. 单轴多级加载岩石破坏声发射特性试验研究J. 岩石力学与工程学报, 2006,10 苏承东, 高保彬, 南华, 等. 不同应力路径下煤样变形破坏过程声发射特征的试验究J. 岩石力学与工程学报, 200911 易武, 孟召平. 岩质边坡声发射特征及失稳预报判据研究J. 岩土力学, 2007, 28(12): 2529253812 钱鸣高,石平五. 矿山压力与岩层控制M . 徐州:中国矿业大学出版社, 2003.13 窦林名,何学秋. 冲击矿压防治理论与技术M . 徐州:中国矿业大学出版社, 2001.14 窦林名,何学秋. 煤矿冲击矿压的分级预测研究M . 徐州:中国矿业大学出版社, 2007.15 彭轩,王浩. 龙固煤矿冲击矿压危险性分析 J . 煤炭技术,2005 (9) : 60 6116 李晓红，夏彬伟，李丹，等. 深埋隧道层状围岩变形特征分析J. 岩土力学，2010，31(4) :1163 1167.任务书学院 矿业工程学院 专业年级 采矿工程 学生姓名 任务下达日期：20XX年1月8日毕业设计日期：20XX年3月12日 至 20XX年6月8日毕业设计题目： 田陈煤矿1.2 Mt/a新井设计毕业设计专题题目：冲击矿压及其防治措施 毕业设计主要内容和要求：以实习矿井田陈煤矿条件为基础，完成田陈煤矿1.2Mt/a新井设计。主要内容包括：矿井概况、矿井工作制度及设计生产能力、井田开拓、首采区设计、采煤方法、矿井通风系统、矿井运输提升等。结合煤矿生产前沿情况，撰写一篇关于冲击矿压及其防治措施的专题论文。论文19390字符。完成翻译一篇，题目为“Optimization of soft rock engineering with particular reference to coal mining”. 院长签字： 指导教师签字：翻译部分英文原文:Optimization of soft rock engineering with particular reference to coal miningAbstract 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 IntroductionThere 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 rocks 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. 1.1Mechanical 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. 1.2Engineering 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. The scheme is shown in Fig. 1. Fig. 1. Engineering system for soft rock.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 structures size and shape, improving planar and cubic layouts of engineering; choosing better strata, and structure orientation, etc., as shown in Fig. 2. Fig. 2. The principle of the optimization process.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. The system is shown in Fig. 3.Fig. 3. Systematic optimization of coal mining in soft rock.2 Engineering examples 2.1Mine 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 12m; 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 58%, and illite 720%. The rocks uniaxial compressive strength is 45 MPa, the average being 4.8 MPa. There are irregular joints in the rock, but distributed irregularly, and the rocks 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 1015. The mine area is 6km long along the strike, and 1km long along its inclination, its area is 6km2, the recoverable reserves are 4,430,000 tons. In the adjacent mine No. 4, the maximum principal stress is NNESSW, approximately along the seams inclined direction. A roadway perpendicular to this direction has convergence values of 70100mm, the damage of roadway supports is 51%. A roadway parallel to the direction of maximum principal stress has convergence values of 2040mm, 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 +110m, the elevation of the main mining level is located at 120m. Strike longwall mining is planned, arranging with uphill and downhill stope areas, as shown in Fig. 4. Fig. 4. 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 20m, 1131m 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. 5. Fig. 5. 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 1481m, and 30.11% of them were arranged to be perpendicular to the maximum principal stress. After amendment, the total length of roadways is 1191m, which is a decrease of 290m, and with only 24.69% of roadways that are perpendicular to the principal horizontal stress, roadways are easier to maintain. As shown in Fig. 6 and Fig. 7. Fig. 6. Layout of the pit bottom and chamber initially designed for Mine No. 5 in Youjiang.Fig. 7. Layout of the pit bottom and chamber after the optimization for Mine No. 5 in Youjiang.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. 8 Fig. 8. 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. 2.2The 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 1215m. The roof and floor of the coal layers are arenaceousargillaceous 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 8km long and 1.5km or so wide. Slopes are inconsistent, the edge angles are 2540, and the bottom of the coalfield is gentle. Affected by tectonic stress in the NWSE direction, there is an inverse fault in the south. After the mine had been developed and put into production, a main roadway at the 250m 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. 9. Fig. 9. 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 arenaceousargillaceous 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 three 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.中文译文煤矿开采中的软岩优化工程摘要软岩工程是一个已引起广泛关注的岩石力学与工程领域中的困难课题。 研究和实际工作已经进行, 但是大部分的工作局限于解决表面的问题。 为克服大变形及长时效应, 必须解决软岩稳定性难题, 形成一个更有效的软岩优化工程系统。本文简要介绍了基于工程实践中的软岩优化程序。1 前言在世界各地有不少软岩工程问题,涉及矿山,公路,铁路,桥梁,隧道, 建筑等。因为软岩体积膨胀,失去稳定性而引发的工程等方面的损失已经发生，这是一个岩石力学领域一直重视的问题。 70年代以来, 各个国家在软岩工程领域投入了大量的研究和实践，但主要精力都集中在设计和加固支撑结构，测量和分析岩石的物理力学性能指标，工程施工方法与岩石结构关系等方面。 在已经发现的软岩工程问题中,涉及到复杂的系统工程包括软岩系统分类,软岩工程设计与施工。 只有考虑到整体系统的优化,才能取得更好的解决办法。一个优化的方式,可以降低工程成本，提高工程稳定性,以实现工程目标。 1.1软岩力学性质及相关工程软岩是一个不平衡的连续介质。 其强度低,单轴抗压强度通常低于30 MPa。有些软岩湿度增加时体积扩大。在一些软岩中裂缝较发育,导致岩石体积膨胀，发生大变形和蠕变。 许多软岩是由两种或多种不同岩性岩石组成的复合型软岩,可依据岩石性能划分等级。 由于软岩强度低, 应力场灵敏度高，矿物质遇水膨胀后，软岩体积扩大 ,能迅速产生大的收敛变形和时效变形, 导致围岩的破害。从软岩的力学性能来看,用数学公式精确描述其众多性能参数的变化规律,是软岩工程技术上的极大的挑战。1.2软岩工程及其优化 在软岩中进行施工,能促使岩体产生大变形,维修的工程也很困难。 此外,岩石体积膨胀, 往往造成岩体支撑结构损坏，围岩丧失稳定性。如果采用强力支撑,以控制变形的围岩, 将增加建造时间，提高工程成本, 有时支撑系统本身已经得到修复，而形成重复支撑。 为了简化施工,降低成本，从而获得最大效益,必须全面地、有系统地进行优化。 在软岩工程的设计与施工中必须了解软岩的物理和力学性能，及围岩应力场,水文地质与工程地质条件。 工程设计方案是根据相邻或相近岩石力学数据与实践相结合，整合多种因素，产生的一个整体的构想。正确的软岩工程系统建立在实践中掌握的各种因素之上 。设计流程如图1 。 图 1 软岩工程系统软岩优化工程是通过支护结构改变围岩性质,使工程趋于稳定。 其关键技术,是避免高应力场和提高围岩的支撑能力。 可行的措施如下:减少外部荷载;优化工程的结构大小和形状, 加强工程平面和立体布置; 选择具有更好结构和方向的地层,等,如图2。 图2 优化原理根据上述思路,以一个在软岩地质条件下的生产煤矿为例。对矿井进行发展系统的综合优化,应考虑相关的因素:实际情况;最佳的开发和生产计划; 消除不利因素; 用简单的方法处理软岩问题。设计第一部分的优化包括:选择矿山开拓方式; 划分开采水平; 并确定主要运输系统的位置。 同样重要的是合理的安排巷道和硐室的位置,设法减少工程之间造成的相互干扰。 水平主应力的开口垂直方向应避开运输路线。 回采巷道的布置应减少开采引起的移动荷载所造成的支持结构的损伤。 进一步优化因涉及到线路的几何形状、尺寸大小、支承结构及施工工艺和方法。 最后,