山西阳泉矿区刘村采煤塌陷机理及数值模拟

doi:10.19657/j.geoscience.1000-8527.2019.018

摘要/Abstract

摘要：

选取山西阳泉矿区单煤层开采引发的强烈地面塌陷作为研究对象,在详细介绍刘村采煤塌陷所处地质环境背景及其发育变形特征的基础上,根据区域岩体工程地质特征,将其划分为12层岩组;运用关键层、复合关键层理论对采煤塌陷机理进行了分析,获取Hoek-Brown岩体力学参数;采用Flac5.0 Extrusion对刘村采煤塌陷坑进行了反演模拟。数值模拟反映各阶段采动裂缝在地表的发育分布情况并计算了最终沉降量,覆盖层裂缝自然修复周期为2个月,基岩裂缝自然修复周期为3个月;采动裂缝最终在平面上呈“θ”形,塌陷中心1和塌陷中心2最终沉降量分别达到4.5 m和4 m,塌陷面积是工作面面积的1.85倍。模拟结果与调查监测数据高度吻合,客观地反映了地表变形和深部覆岩塌陷的发展变化过程,为塌陷机理分析起到了帮助作用。该套岩体力学参数与模拟方法适用于阳泉矿区采煤塌陷精准预测。

关键词: 采煤塌陷, 塌陷特征, 塌陷机理, 数值模拟, 岩体力学参数

Abstract:

In this paper, we investigated the single seam coal mining subsidence, and introduced in detail the geo-environment background, developing features and deformation characteristics of the Liucun coal mining subsidence of Yangquan mining area in Shanxi. Based on the geological characteristics of the rocks, 12 groups were divided and their formation mechanism was analyzed by key stratum and composite key stratum theory. Subsequently, the Hoek-Brown rock mechanical parameters were obtained, followed by inverse modeling by Flac5.0 Extrusion. Numerical simulation reflects the development and distribution of mining-induced fissures on the surface at different stages, and calculates the final magnitude of subsidence. The natural recovery period of fissures in overburden and bedrocks was estimated to be 2 and 3 months, respectively, and the fissures finally present a “θ” shape in the plane. The final magnitudes of No.1 and No.2 coal mining subsidence centers reach 4.5 m and 4 m, respectively, with the subsidence area being 1.85 times of the workface area. The results are highly consistent with the survey monitoring data, and can reflect the development process of the surface deformation and deep overburden collapse accurately, which is beneficial to subsidence mechanism analysis. The rock mechanical parameters and the simulation methods are applicable to accurate prediction on mining subsidence in Yangquan mining area.

Key words: coal mining subsidence, subsidence characteristic, subsidence mechanism, numerical simulation, rock mechanical parameter

中图分类号:

P618.11

张超, 张宇飞, 孙莹洁, 姚亚辉. 山西阳泉矿区刘村采煤塌陷机理及数值模拟[J]. 现代地质, 2020, 34(02): 289-296.

ZHANG Chao, ZHANG Yufei, SUN Yingjie, YAO Yahui. Mechanism and Numerical Simulation of Liucun Coal Mining Subsidence of Yangquan Mining Area in Shanxi[J]. Geoscience, 2020, 34(02): 289-296.

图/表 12

图1 研究区构造纲要图 (ⅠⅠ'、ⅡⅡ'和ⅢⅢ'为工程地质剖面)

Fig.1 Simplified structural map of the study area

图2 剖面ⅠⅠ'地层结构图

Fig.2 Stratigraphic structure across profile ⅠⅠ'

图3 刘村采煤塌陷裂缝分布示意及现场照片(等值线单位:m)

Fig.3 Sketch map and photos of subsidence fissure patterns in the Liucun coal mining subsidence

图4 外围裂缝开裂变形过程示意图

Fig.4 Schematic diagrams for the deformation processes of the peripheral fissures

图5 剖面ⅠⅠ'塌陷机理示意图

Fig.5 Subsidence mechanism sketch map of profile ⅠⅠ'

表1 研究区岩石力学参数

Table1 Mechanical parameters of rocks in the study area

岩组	地层岩性	密度/(kg/m³)	体积模量/GPa	剪切模量/GPa	弹性模量/GPa	泊松比	内聚力/MPa	内摩擦角/(°)
1	黄土、红黏土	1380	0.03	0.01	0.034	0.3	0.01	15

表2 Hoek-Brown岩体力学参数

Table 2 Hoek-Brown rock mechanical parameters

岩组	地层岩性	密度/ (kg/m³)	σ_ci/ MPa	μ	GSI	m_i	D
2	砂质页岩夹砂岩	2 610	40.3	0.24	40	7	0.8
3	中粒砂岩	2 630	75.6	0.23	50	15	0.8
4	粉砂岩、炭质页岩	2 610	44.0	0.24	40	7	0.8
5	中粒砂岩	2 630	75.6	0.23	50	17	0.8
6	砂质页岩夹煤层	2 570	29.3	0.28	40	4	0.8
7	中细粒砂岩、页岩互层	2 610	47.0	0.24	45	10	0.8
8	中粗粒砂岩、页岩互层	2 610	49.2	0.24	50	12	0.8
9	粗粒砂岩	2 630	110.6	0.23	50	19	0.8
10	砂质页岩、粉砂岩、灰岩	2 690	65.3	0.22	60	8	1.0
11	15^#煤层	1 459	33.7	0.24	50	4	0.8
12	砂岩、页岩	2 610	53.2	0.24	60	7	0.3

图6 月采空区中心点变形曲线(2016年)

Fig.6 Deformation curves of monthly mined-out area center

图7 不同时间节点采动裂缝发育分布

Fig.7 Numerical simulation results of the final subsidence

图8 达到最终塌陷时数值模拟结果

Fig.8 Numerical simulation results of the final subsidence

图9 刘村采煤塌陷坑最终塌陷量等值线图

Fig.9 Contour map of the final subsidence in Liucun

表3 岩移角对比(°)

Table 3 Contrast of rock moving angles(°)

数据源	ⅠⅠ' 北	ⅠⅠ' 南	ⅡⅡ' 西	ⅡⅡ' 东	ⅢⅢ' 西	ⅢⅢ' 东
调查数据	78	64	64	65	67
模拟结果	77	63	63	62	66	67

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