倾斜长壁开采的沿空成巷试验研究.pdf

文章编号 1003- 5923 2002 01- 0043- 02 倾斜长壁开采的沿空成巷试验研究 熊仁钦1, 吕力行1, 覃惠宣2, 旷明生2 1. 湘潭工学院, 湖南 湘潭 411201; 2. 罗城矿务局, 广西 罗城 546400 摘 要 根据呼略矿倾斜长壁开采的工业性试验, 以及沿空巷道的矿压观测成果, 分析了应用沿空成巷技 术的力学原理, 说明了利用密集支柱和矸石带作为巷旁支护所取得的较好效果。 关键词 倾斜长壁; 沿空成巷; 巷旁支护 中图分类号 TD322. 3 文献标识码 A 无煤柱开采是一种先进的煤矿开采方法, 其突 出优点在于适应矿山压力的分布规律, 有利于改善 巷道维护和稳定; 有利于合理开发煤炭资源, 提高 煤炭回采率; 有利于安全生产。 有资料报道, 无煤柱 开采一般可使回采率提高10～20 , 有的矿甚至 提高25 ～30。 早在二十世纪六十年代, 无煤柱 开采就从国外引入中国进行试验, 并在全国普遍推 广, 取得了可观的效益。 倾斜长壁开采就从国外引 入中国进行试验, 并在全国普遍推广, 取得了可观 的效益。 倾斜长壁开采和沿空成巷技术就是无煤柱 开采的一种较好的方法。 广西罗城矿务局呼略矿, 长期以来采用刀柱采 煤法, 木材支护, 产量低, 坑木消耗量大, 煤炭回收 率低, 成本高。 对该矿进行了巷道布置和采煤方法 改革试验, 将传统的刀柱法开采改为倾斜长壁开 采, 采用沿空成巷技术, 并进行矿压观测和支护设 计。 经过几年的实践和研究, 试验取得了成功。 1 生产技术条件 该矿704采面为试验工作面, 它位于二水平七 采区南翼中段, 上部以702主巷 182 m 标高为界, 下部为704主巷为界, 南面到采区边界线, 北面到七 采区副下山。 该区段走向长440 m, 斜长200～240 m, 可采面积81400 m 2。 煤厚 0. 7～3. 2 m, 平均为 1. 8～2. 2 m, 变化幅度大。 煤层结构较复杂, 含夹 矸2～5层, 夹矸为云母炭质页岩, 夹矸最厚时可达 1. 2 m。 煤层倾角为13 30′ ～16 , 平均为14 30′ 。 直 接顶为16 m 厚的灰质页岩, 较软, 遇水易泥化掉 落。 老顶为厚层罗城贝灰岩, 厚约100 m, 层内裂隙 发育, 有导水性, 为该地层的主要含水层。 直接底为 炭质页岩和泥质页岩, 较软, 遇水膨胀, 厚3～5 m。 老底为黄金灰岩, 厚而坚硬。 该煤层顶底板的岩石 力学性质指标见表1。 煤层赋存复杂, 为不稳定结构 中厚煤层。 煤尘无爆炸性。 煤层自燃发火属三类。 表1 岩石力学性质指标 名称 试件 个数 点荷载指数 Is/MPa 偏离度 Rc / MPa Rt / MPa 备 注 老顶50. 154109标准试件 直接顶232. 9060. 36533. 421. 25 直接底162. 440. 38528. 11. 05 2 巷道布置和采煤方法改革 多年来, 呼略矿所采煤层结构复杂, 煤层顶板 强度低, 底板质软, 煤层内含多层夹矸, 且变化很 大, 采面采高很不稳定, 导致不能采用正规采煤方 法开采, 而一直沿用刀柱法开采。 在1989年和1992 年, 呼略矿曾两次使用金属摩擦支柱进行开采方法 改革试验, 采用的是走向长壁开采, 都因缺乏矿压 观测资料和科学依据而使试验失败。 其根本问题 是, 工作面顶板岩层活动规律不清楚, 生产技术措 施针对性不强, 木支柱支护安全性差, 制约了生产 的进一步发展。 因此, 采煤方法的改革势在必行。 呼略矿采煤方法改革试验, 选在704面进行, 在 巷道布置上采用倾斜长壁仰斜开采。 工作面由下而 上前进回采, 采用沿空成巷巷道作为本条带的进风 巷和运煤巷, 并保留下来作为下一条带的回风巷。 由于条件限制, 该工作面支护采用 HZWA- 2300 金属摩擦支柱和 HDJA- 800金属铰接顶梁。 采用 收稿日期 2001- 08- 15 作者简介 熊仁钦 1945- , 男, 教授, 从事矿山压力与岩层控制的研究。 43 矿山压力与顶板管理 2002. №1 图1 工作面布置示意图 正悬臂齐梁齐柱布置, 3～4排控顶, 支柱排距0. 8 m, 柱距0. 6 m, 最大控顶距3. 4 m, 最小控顶距2. 6 m。 人工打眼, 放炮落煤。 采用全部垮落法管理顶 板。 而沿空巷道则采用无预掘沿空留巷, 即所谓的 沿空巷。 它是在采空区边缘的低压区, 利用棚子、 密 柱和矸石垛支撑顶板, 在已开采出的空间留出一条 巷道。 巷道的断面尺寸为1. 81. 8 m, 棚距为0. 8 m, 采用 18 cm 的木材支护。 巷旁支护采用单排密 柱支设在两棚之间, 密柱旁的矸石垛宽度为1. 5 m 左右, 必须接顶。 这样的开采方法, 可节省大量的巷 道掘进费用, 降低生产成本。 图2是所采用的沿空成 巷巷道的支护方式和规格尺寸示意图。 图2 沿空成巷巷道支护方式和规格示意图 倾斜长壁采煤法是一种较先进的采煤方法。 它 巷道布置简单, 占用设备少, 技术经济效益比较显 著。 采煤方法能否成功, 关键是围岩的控制问题, 主 要是顶板管理的问题。 要管理好顶板就必须摸清顶 板岩层的活动规律, 及其对回采工作的影响。 为此, 对该试验工作面及巷道进行了矿压观测与分析。 3 沿空巷道变形观测及分析 由于工作面走向长只有50 m, 根据研究的目 的和内容, 只在回采工作面的中部设一观测区, 区 内设三条观测线, 按观测排分别设置顶板下沉量、 活柱缩量、 以及支柱载荷观测点。 在运输巷内, 即沿 空巷道内, 从下部平巷起每10 m 设一个观测站, 测 定棚梁和底板的相对位移, 两棚腿的相对位移量, 以及巷道靠采空区一侧顶板的下沉量。 选择巷道变 形相对较大的那个观测站为例, 来说明开采过程中 沿空巷道的状况, 该测站距下部平巷30 m, 图3是 该点巷道变形随工作面推进距离的关系曲线。 图3 沿空巷道变形随工作面推进距离的关系曲线 从直接顶岩层组成来看, 其厚度为16 m, 被煤 线 分割为 四层, 紧贴煤 层的那一 层直接 顶厚 3. 5 m, 直接顶单轴抗压强度 RC 33. 42 MPa, 抗 拉强度 Rt 1. 25 MPa, 其强度指数 D 50～70, 初 次垮落距为8～9 m, 按原煤炭部颁发的缓倾斜煤 层工作面顶板分类试行方案, 该煤层直接顶属Ⅱ类 中等稳定顶板。 但由于该煤层直接顶分层厚度大, 完整性好, 裂隙不发育, 因而易形成整体的断裂垮 落, 产生有显现但不强烈的周期来压。 从沿空巷道 变形观测分析来看, 由于最大的变形是棚梁和底板 的相对位移, 其值也只有162 mm, 两棚腿的相对位 移只有50 mm, 顶板下沉量为80 mm 左右, 而且没 有继续产生较大变形的趋势, 说明巷道是稳定的, 支护是合理的, 沿空成巷技术在这种条件下是成功 的。 4 结 语 由于该工作面采用倾斜长壁仰斜开采, 巷道掘 进 率 大 幅 度 降 低, 比 刀 柱 法 开 采 少 掘 巷 道 565 m/ 万 t, 产量提高了262, 取得了产量高、 坑 耗少、 安全好的效果。 呼略矿从1994年开始使用沿 空成巷技术, 至今运行情况良好。 1 由于直接顶比较厚, 冒落后能充满采空 区, 使得上覆岩层运动比较缓和, 能尽快取得平衡, 有利于沿空巷道的稳定。 这是沿空成巷技术能够应 用的关键。 2 该煤层夹矸较多, 累计厚度一般在0. 5～ 1 m左右, 在采煤的同时, 应及时将夹矸检出充填 老塘和砌矸石带, 这样可降低顶板的下沉量, 减少 顶板冒落对工作面的影响。 3 沿空巷道的巷旁支护是密柱和矸石带, 要 保证支护的规格质量, 使之能有效的支撑顶板和减 少老塘漏风。 4 当沿空巷道成为下一条带的回风巷时, 采 煤工作面控顶区以下的棚子和密柱可以适时回收, 以便再行利用, 这样可以降低坑耗。 44 2002. №1 矿山压力与顶板管理 矿山压力 与顶板管理 ENGLISH ABSTRACTS Key theory and technique of coal entry bolt supporting HOU Chao- jiong This paper expounds the key theory and technique about developing coal drift bolt supporting,which mainly con- tainedthe theory of consolidating rock strength with bolt supporting, the high strength bolt supporting system, bolting dynamic system design procedures, coal roadway bolting un- der the difficulty and complex conditions,big/small struc- tures stability theory of roadway surrounding rock driven a- long goaf in fully mechanized top-coal caving face, etc. Some views and advices of developing bolt supporting coal drift are put forward. Study on parameters of top coal fracture damage in fully mechanized top-coal caving faceJIN Zhong-ming etc. According to material damage characteristic relation, the relation between the damage variation, damage coefficient, coal mass constant and the fracture strength of coal mass, mining depth and change relation of damage variation in ad- vance process of working face are obtained by three dimension fracture test of big coal sample,top coal deation observe in working face and finite element numeral analysis. The conclusions show that the change law of damage parameters is reliable. Change of damage variation D is exponential func- tion in advance process of working face.This law is impor- tant significance to forecast abutment pressure distribution and top coal caving feature. The design and practice on distressing engineering of mining soft- rock roadwayHE Fu- lian etc. Gob- side entries of fully mechanized top- coal caving face mostly are mining soft-rock roadways,where roadways de- ation destruction is intense and maintenance is difficult. This paper puts forward the general scheme of technology about how to per distressing engineering of fully mecha- nized coal winning and caving drifts on the basis of field-site investigation, according to practical production condition of geology of Xinji Mine. T hrough computer numerical simula- tion,the specific technology parameters had been designed and determined. Practice proved that the designed parame- ters were reasonable and practicable, and remarkable econo- my and technology benefit had been obtained. Development test of the road ed along next goaf by longwall mining to the riseXIONG Ren- qin etc. Based on the profitable test of Hulue Mine by longwall mining to the rise and the strata behaviors measurement of the road ed along next goaf, the mechanical principle of the road support is analyzed. It is explained that the good ef- fect has been obtained through successfully using closed- standing supports and waste wall as support beside the road- way. Discussion on underground longwall mining for extraction of Indian shallow thick coal seams under hard roof rocks JIANG Fu- xing etc. This paper presents a technological plan- a combined longwall mining integrated fully mechanized longwall mining along seam floor first with fully mechanized longwall sublevel caving mining afterwards according to the conditions of Indian shallow thick seams under hard roof rocks and proves its advantages and feasibility.It also introduces a for monitoring the location of fracturing line of hard roof rocks.The is of important value for application in preventing the dynamic impact when hard roof weighting occurs and ensuring the safe production. The key technical problems and their solvable ways of mechanized coal mining in high inclined seamWU Yong- ping Based on the analysis of its past records and current situ- ations about high inclined seam mining,the paper probes into the key technical problems and puts forward the solvable ways combined with the practices of full mechanized coal mining at home which applied in high inclined seam. Critical catastrophic analysis of instability of combina- torial key strata in shallow coal seamXIE Sheng- hua etc. In this paper,the mechanical model of combinatorial key strata is analyzed with the help of the of catastrophe theory. The expression of the total potential energy function for this system is derived.This system can be described by the cusp catastrophe model. The bifurcation set which makes this system to loss its stability of the combinatorial key strata in the horizontal and vertical force control space is obtained, step sinking conditions of roof and its structure stability are quantitatively analyzed. It is proved that the result is practi- cal. Moving features of top-coal and its roof strata in hard thick- top- coal fully mechanized caving faceSUO Yong- lu etc. Based upon the site-surveying the moving features of the top and its roof trata as well as the falling configuration of the top-coal in hard thick- top- coal fully mechanized caving face after pre- weakenned the top-coal are analysized and summa- rized.It has been found that to pre-weaken the top-coal makes the range of top- coal and its roof strata motion in- crease , the roof strata breaking step decrease , the top- coal falling angle increase,the block size fallen top-coal largely re- duce , and the falling configuration of the top- coal is likely as a pillar shape . Experimental research on top-coal caving of“B“props under hard coal seam of middling thicknessCHAI Jing etc. Based on the field observation results of ground pres- sure,the paper studies the movement characteristics of top- coal and the roof at 12212 working face adopting props in Hongshiyan Mine. It points out that blasting technique is needed at top-coal caving face under the hard seam of3. 5m thickness. Ground pressure observing of double- longwall faces in mining on confined aquiferLUO Li-ping etc. Double longwall face mining on confined aquifer is sel- dom adopted in domestic and overseas, compared with other mining system study of ground pressure between double long- wall faces is one of the important issues.Based on the 2635double longwall mining panel,mining and geological condition in Yangzhuang colliery, a rational staggered dis- tance of double longwall faces is proposed to be within10m, by means of observing the changes of abutment pressure insi- tu. Estimate of surface movement and rock movement pa- rameter analysis under thick soil layer miningLI De-hai etc. T he regularityand parameterof surface movement aroused by mining under thick soil layer and thin base rock have its obvious characteristic and regularity. Under stratum condition of thick soil layer, we can study it as random medi- um and use probability integral to estimate surface movement.According to the stratum of thick soil layer in Yongxia and Jiaozuo coal area, the character and parameter of surface movement under thick soil layer by use of mathe- matical ways are analyzed,and the function relation between the parameters of s森face movement and the geology and coal mining condition can be found. 109 矿山压力与顶板管理 2001. №3