【作者】 刘飞；

【导师】 张农；

【作者基本信息】 中国矿业大学 ， 采矿工程， 2015， 硕士

【摘要】 本文以朱集东煤矿11-2煤层首采面开采后覆岩运移规律和13-1煤层首采面回采巷道的布置为研究对象,将岩层的下沉简化为四周简支的薄板挠曲问题对其进行数学描述,采用预测地表沉陷的概率积分法研究了煤层开采后覆岩内部位移场,运用相似模拟实验研究了11-2煤层顶板岩层的活动规律及其对13-1煤层的扰动,基于FLAC3D数值实验提出不稳定性指数概念,以此对上部回采巷道位置进行优化。取得研究成果如下:(1)将岩层的下沉简化为四周简支的薄板挠曲问题,对岩层的移动进行数学描述,给出单一缓斜岩层的移动的基本公式及边界条件,采用分析地表移动基本规律的概率积分法分析了覆岩内部位移场。(2)采用相似模拟实验研究了上行开采顶板活动规律及对上覆煤层的扰动。认为随11-2煤层首采面的推进,直接顶初次来压后基本顶发生周期性的破断,来压步距为20~30m。13-1煤层位于11-2煤层回采后的弯曲下沉带内,煤层整体下沉,煤层水平位移的最大值分别为-130.5mm和99.8mm、最大下沉量为1.55m、最大膨胀和压缩变形量为15.79mm和19.07mm,表明13-1煤层整体性遭到一定的破坏,变形量不大,仍能保持连续性,能够满足上行开采的条件。(3)采用FLAC3D数值计算分析了层间距和水平错距对上行开采上覆煤层巷道稳定性的影响。依据数值计算结果提出不稳定性指数的概念及计算公式,分析不同区域巷道不稳定指数云图对上覆煤层回采巷道的位置进行优化,确定朱集东煤矿上覆13-1煤层首采面回采巷道的合理位置为相对于下伏11-2煤层首采面回采巷道内错15~20m。(4)朱集东煤矿13-1煤层首采面1111(3)轨道顺槽相对于11-2煤层首采面1111(1)回采巷道内错15m掘进,巷道处于卸压区内应力环境较好且煤层结构能够保持完整性,根据数值计算结果给出掘进期间锚网支护方案,掘进后累计28天内两帮累计变形量为40mm。顶底板累计移近量为114mm。设计支护方案及参数能控制巷道围岩掘进期间的大变形,巷道整体控制效果较好。更多还原

【Abstract】 Movement Law of overlying strata and layout of the overlying mining gateway in 13-1 coal seam were studied after the first workface of 11-2 coal seam mined out in East Zhuji coal mine. The strata subsidence was simplified as deflection of a thin plate which was simply supported on four sides in order to describe it by mathematical method. Probability integral method which is often disappeared in predicting the ground surface subsidence was used to analysis the internal displacement of overlying strata after protective layer mined out. Similar simulation experiment was also carried out in the laboratory to research on movement law of overlying strata and mining disturbance on 13-1 coal seam, instability index was put forward based on FLAC3 D numerical experiment to analysis the position optimization on mining gateway of 1111(3) workface. Results obtained in this paper were shown as follows:(1) The strata subsidence was simplified as deflection of a thin plate which was simply supported on four sides in order to describe it by mathematical method, in which a formula and boundary conditions of single gently inclined strata were put forward. Probability integral method which is often disappeared in predicting the ground surface subsidence was used to analysis the internal displacement of overlying strata.(2) Similar simulation experiment was carried out in the laboratory to research on movement law of overlying strata and mining disturbance on 13-1 coal seam. Main roof would break periodically after immediate roof broke and the roof weighting step was nearly 20-30 m with the advance of workface. 13-1 coal seam sank concordantly with the maximum horizontal and vertical displacement were-130.5mm, 99.8mm and 1.55 m as it located at the bending zone of 11-2 coal seam. The coal seam would also suffer a breakage of volume with the expansion and compression of 15.79 mm and 19.07 mm. The small deformation of 13-1coal seam shown that though the entirety suffered a certain degree of damage, it could maintain continuity which satisfied the basic bargain ascending mining method.(3) Finite element numerical calculation software FLAC3 D was used to analysis the influence of interlayer distance and alternate distance on the stability of gateway. The concept and calculation formula of instability index was put forward based on result of numerical calculation. We optimized the layout of overlying mining gateway though analyzing the instability index of different zone and the best position is ensured to left a internal displacement of 15m-20 m to the mining gateway of 1111(1) face in 11-2 coal seam.(4) The mining gateway of 1111(3) face in 13-1 coal seam was excavated as designed to left a internal displacement of 15 m to the mining gateway of 1111(1) face in 11-2 coal seam where the stress environment was relative good and the structure could keep complete. Bolt support parameters during the driving period was decided based on the results of numerical calculation experiment, it efficiently kept gateway stable for having a cumulative deformation of 114 mm between roof and floor, besides that the gateway working slopes also had a small deformation of 40 mm. Small deformation of the gateway surround rock shown that the bolt support program could keep the gateway away from suffering huge deformation in the driving period.更多还原