College of Mining Engineering, Taiyuan University of Technology
College of Safety and Emergency Management Engineering, Taiyuan University ofTechnology

为确定倾斜特厚煤层综放工作面沿空掘巷区段煤柱的合理尺寸,以孟家窑煤矿 11503 综放工作面沿空掘巷为工程背景,基于倾斜煤层基本顶破断之后的岩层结构,建立倾斜煤层工作面“大、小结构”力学模型,推导出适合小结构布置区域的低应力场范围表达式,并通过“尖点突变”理论分析区段煤柱发生失稳突变的充要条件。 采用 FLAC3D模拟不同尺寸煤柱的受力及围岩变形规律。 研究表明:受到煤层倾角和基本顶关键块回转挤压的影响,煤柱内部破坏形式主要为剪切破坏,破坏区域主要集中在其上部偏向采空区位置;随着煤柱宽度的增大,在沿空掘巷小范围内上覆岩层压力由实体煤承担逐渐转向由煤柱承担;结合应力场、位移场和塑性区变化情况,最终确定煤柱的合理尺寸为 15 m。 通过分析不同采掘阶段沿空巷道围岩应力分布和演化特征,提出适合不同阶段的围岩控制方案。 结合现场工程实践表明,15 m 煤柱宽度及围岩控制方案能够满足巷道稳定性要求。

To identify the appropriate coal pillar size in district sublevel of gob-side entry driving infully mechanized caving face in an inclined extra-thick coal seam, the 11503 fully mechanized cavingface in Mengjiayao Coal Mine was chosen as the engineering background. A mechanical model of “largeand small structure” in an inclined coal seam working face was developed, considering the strata struc-ture following the collapse of main roof. The theorem defining the low stress field range suitable for loca-ting the small structure was derived, and the conditions necessary and sufficient for the instability catas-trophe of coal pillar in district sublevel were analyzed using “cusp catastrophe” theory. Moreover, thestress of coal pillars with different sizes and the deformation law of surrounding rock was simulated byFLAC3D. The research findings indicated that shear failure was the primary internal failure mode in coalpillars due to the inclination angle of the coal seam and the rotary-extrusion of key blocks in the mainroof. The failure region was mainly concentrated in the upper portion of the coal pillar, near the gob area.With the increase of the coal pillar width, small-range of pressure in overlying strata of gob-side entrydriving gradually transferred from intact coal side to coal pillar side. After considering the changes instress field, displacement field, and plastic zone, the reasonable size of coal pillar was determined to be15 meters. By analyzing the stress distribution and evolution characteristics of surrounding rock in thegob-side entry at various mining stages, different surrounding rock control schemes were proposed. Engi-neering practice has demonstrated that a coal pillar with a width of 15 m, along with the correspondingsurrounding rock control scheme, can meet the stability requirements of roadway.

国家自然科学基金项目(U1810104);山西省自然科学基金项目(201901D111047)

1 工程概况
2 煤柱宽度理论分析
2.1 煤柱宽度理论计算
2.2 煤柱宽度合理性验证
1) 区段煤柱的力学模型
2) 区段煤柱尖点突变模型
3) 失稳机理分析
3 煤柱宽度数值模拟
3.1 数值模型
3.2 塑性区分布特征
3.3 巷道围岩形变规律
3.4 沿空掘巷围岩应力分布
4 沿空掘巷围岩分区控制技术
4.1 采掘交锋巷道承压来源
4.2 采掘交锋支护方案
4.3 支护效果
5 结 论