大倾角采场围岩应力分布及矸石充填特征的倾角效应研究

高利军; 晋发东; 梁东宇; 杨文斌; 汤业鹏; 王同

doi:10.13272/j.issn.1671-251x.2023100064

大倾角采场围岩应力分布及矸石充填特征的倾角效应研究

doi: 10.13272/j.issn.1671-251x.2023100064

1.
华亭煤业集团赤城煤矿有限责任公司，甘肃平凉　744000
2.
太原理工大学安全与应急管理工程学院，山西太原　030024
3.
西安科技大学能源学院，陕西西安 710054

基金项目: 山西省重点研发计划项目（基于BIM 的三维智能化矿井透水应急救援平台研发）。

详细信息

作者简介:
高利军（1981—），男，陕西榆林人，工程师，主要从事煤矿生产技术管理工作，E-mail：2522771070@qq.com

中图分类号: TD323
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出版历程
- 收稿日期: 2023-10-22
- 修回日期: 2024-03-13
- 网络出版日期: 2024-03-26

Study on the stress distribution of surrounding rock and the inclination effect of gangue filling features in steeply dipping mining sites

1.
Huating Coal Industry Group Chicheng Coal Mine Co., Ltd., Pingliang 744000, China
2.
College of Safety and Emergency Management Engineering, Taiyuan University of Technology, Taiyuan 030024, China
3.
College of Energy Engineering, Xi'an University of Science and Technology, Xi'an 710054, China

摘要

摘要: 煤层倾角是造成大倾角采场采动力学行为呈现复杂性、特殊性，诱发众多灾害事故的重要因素之一，为揭示煤层倾角对大倾角采场围岩控制及矿压显现特征的影响规律，采用物理相似模拟和数值计算相结合的研究方法，在综合分析了大倾角工作面顶板破断运移及矸石滑滚充填特征的基础上，利用有限元−离散元（FLAC2D-PFC2D）耦合算法建立了不同倾角的大倾角采场耦合数值模型，研究了大倾角采场围岩应力分布及矸石充填特征的倾角效应。结果表明：① 采动作用下，大倾角采场顶底板内围岩应力均呈非对称拱形分布，随着煤层倾角增大，拱形垂直应力释放区范围和向上部偏移程度逐渐增大，但水平应力释放区范围和应力值逐渐减小，无论是垂直应力还是水平应力都易在工作面上下端头顶板处出现应力集中，但最大集中应力会随煤层倾角的增大而减小；大倾角工作面顶底板内应力大小和传递方向均存在非对称特征，随着煤层倾角增大，工作面顶底板应力拱高逐渐降低，围岩应力的传递方向以围岩涌向采出空间为主，由初始近似竖直方向逐渐偏转趋于工作面垂向。② 工作面顶板破断及矸石的滑滚充填具有时序性和分区演化特性，并随煤层倾角的改变而呈现一定的倾角效应。随着煤层倾角增大，直接顶的初次破断位置将逐渐向工作面倾向上部区域转移，同时由于重力沿工作面倾向的分力变大，矸石沿倾向的充填程度更为密实，但充填长度减小，工作面中上部区域高位岩层的破碎程度和空洞范围增大。③ 采空区内矸石对围岩的作用机制主要体现在提供侧向应力和竖向支撑2个方面，且受矸石重力作用影响较大，会随煤层倾角改变呈现较强的倾角效应。
- 大倾角煤层 /
- 围岩应力 /
- 矸石充填 /
- 倾角效应 /
- 采动应力 /
- 顶板破断
Abstract: The dip angle of coal seam is one of the important factors that cause the complexity and particularity of the mining dynamic behavior of the large dip angle stope and induce many disasters and accidents. In order to reveal the influence law of the dip angle of coal seam on the control of surrounding rock and the characteristics of mine pressure in the large dip angle stope, the research method of physical similarity simulation and numerical calculation is adopted. Based on a comprehensive analysis of the features of roof crack and gangue sliding and rolling filling in steeply dipping working faces, a finite element discrete element (FLAC2D-PFC2D) coupling algorithm is used to establish a coupled numerical model of high angle mining areas with different inclinations. The stress distribution of surrounding rock and the inclination effect of gangue filling features in steeply dipping mining areas are studied. The results show the following points. ① Under the action of mining, the stress distribution of the surrounding rock in the roof and floor of the high angle mining area is asymmetric arched. As the dip angle of the coal seam increases, the range of the arched vertical stress release zone and the degree of upward displacement gradually increase. But the range and force value of the horizontal stress release zone gradually decrease. Both vertical and horizontal stresses are prone to stress concentration at the top and bottom of the working face. But the maximum concentrated stress value will decrease with the increase of coal seam inclination angle. The stress magnitude and transmission direction inside the roof and floor of the steeply dipping working face exhibit asymmetric features. As the coal seam dip angle increases, the stress arch height of the working face roof and floor gradually decreases. The transmission direction of surrounding rock stress is mainly towards the mining space, and gradually deviates from the initial approximate vertical direction towards the vertical direction of the working face. ② The roof crack of the working face and the sliding and filling of gangue exhibit temporal and regional evolution features, and exhibit a certain dip angle effect with the change of coal seam dip angle. As the inclination angle of the coal seam increases, the initial breaking position of the direct roof will gradually shift towards the upper area of the working face. At the same time, due to the increased force of gravity along the inclination direction of the working face, the filling degree of the gangue along the inclination direction will be more dense. But the filling length will decrease. As the inclination angle of the coal seam increases, the degree of crack and the range of voids in the high-level rock layers in the upper and middle areas of the working face will also increase. ③ The mechanism of the action of gangue on the surrounding rock in the goaf is mainly reflected in providing lateral stress and vertical support, and is greatly affected by the gravity of gangue, which will show a strong inclination effect with the change of coal seam inclination angle.
- steeply dipping coal seam /
- surrounding rock stress /
- gangue filling /
- angle effect /
- mining induced stress /
- roof crack

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图 1 工作面综合柱状图

Figure 1. Geological column of working face

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图 2 顶板破断及矸石充填特征

Figure 2. Features of roof breaking and gangue filling

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图 3 大倾角煤层开采的倾向数值模型

Figure 3. Numerical model of propensity for large-dip coal seam mining

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图 4 等效重力场法模拟不同倾角的模型

Figure 4. Simulating models with different inclination angles using the equivalent gravity field method

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图 5 不同倾角模型垂直应力分布

Figure 5. Vertical stress distribution of different inclination models

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图 6 不同倾角模型水平应力分布

Figure 6. Horizontal stress distribution of different inclination models

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图 7 45°倾角主应力分布

Figure 7. Principal stress distribution at 45°

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图 8 不同倾角围岩应力拱及偏转界线

Figure 8. Stress arches and deflection boundaries of surrounding rocks with different inclinations

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图 9 不同倾角下采动主应力变化量分布

Figure 9. Distribution of changes of mining principal stress at different inclinations

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图 10 不同倾角工作面顶板垮落及矸石充填形态特征

Figure 10. Features of roof collapsing and gangue filling pattern of working face with different inclination angles

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图 11 不同倾角条件下垮落充填矸石的孔隙率分布特征

Figure 11. Features of porosity distribution of falling gangue under different inclination angles

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图 12 大倾角工作面倾向矸石力链及围岩应力分布特征

Figure 12. Features of gangue force chain and surrounding rock stress distribution in the working face with steeply dipping coal seam

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图 13 不同倾角下矸石对下侧边界煤岩体侧向压力分布曲线

Figure 13. Lateral pressure distribution curve of gangue on lower coal and rock body under different inclination angles

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图 14 不同倾角下矸石对底板垂直应力分布曲线

Figure 14. Vertical stress distribution curve of gangue on floor under different inclination angles

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表 1 FLAC模型煤岩数值参数

Table 1. Numerical parameters of coal and rock in the FLAC model

岩性	密度/ （kg·m⁻³）	体积模量/ MPa	剪切模量/ MPa	抗拉强度/ MPa	黏聚力/ MPa	内摩擦角/ （ ° ）
上覆岩层	2 550	9 435	7 876	2.9	3.9	37.5
细砂岩	2 430	7 150	6 460	2.0	2.9	35.2
中砂岩	2 550	9 435	7 876	2.9	3.9	37.5
粗砂岩	2 760	12 300	13 216	3.6	4.8	26.0
4号煤层	1 350	2 381	1 163	0.6	1.3	32.9
粗砂岩	2 760	12 300	13 216	3.6	4.8	26.0
细砂岩	2 430	7 150	6 460	2.0	2.9	35.2
夹矸	2 650	8 640	8 250	2.3	2.7	34.5
5号煤层	1 350	2 381	1 163	0.6	1.3	32.9
粉砂岩	2 312	7 241	6 460	2.7	3.2	27.0
粗砂岩	2 760	12 300	13 216	3.6	4.8	26.0
砾岩	2 492	9 846	11 260	3.0	3.6	28.5
下伏岩层	2 760	12 300	13 216	3.6	4.8	26.0

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表 2 PFC模型煤岩细观数值参数

Table 2. Numerical parameters of coal and rock in the PFC model

细观参数	煤	夹矸	细砂岩
黏结键的黏结模量/GPa	2.31	8.32	7.16
黏结键的刚度比	1.78	1.20	1.30
黏结键的法向强度/MPa	6.5	18.7	13.2
黏结键的切向强度/MPa	6.5	18.7	13.2
黏结键的内摩擦角/（°）	32.9	34.5	35.2
颗粒半径范围/m	0.10～0.20	0.10～0.20	0.10～0.20
颗粒密度/（kg·m⁻³）	1 350	2 650	2 430

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表 3 不同倾角条件下矸石充填形态特征参数

Table 3. Characteristic parameters of gangue filling pattern under different inclination angles

参数	倾角/(°)
参数	35	40	45	50	55
充填长度/m	61.7	61.0	59.6	58.2	57.0
接顶长度/m	8.6	9.8	11.3	14.7	18.4

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