倾斜煤层断顶卸压模型试验研究

Modeling test based study on roof cutting for pressure unloading in inclined coal seam

为研究倾斜煤层断顶卸压位置对煤岩体稳定性的影响,以双鸭山某矿的回采工作面为试验原型,开展地质力学模型试验。采用相似材料和模型架,模拟工作面回采区域的地质构造及煤层赋存的应力状态,通过数字图像相关方法(DICM)实时测试模型断顶前后煤柱、煤体和顶板区域的变形场。结果表明:在巷道紧邻煤柱上部实施断顶,巷道及煤柱内侧出现明显变形集中区域,上覆岩体下沉,煤柱内侧受拉伸;在相邻采空区紧邻煤柱实施断顶,粗砂岩和细砂岩沿岩层界面发生界面滑动,但位移量较小;在煤柱外边缘以里3 m处实施断顶,采空区一侧煤体受上覆顶板压力作用发生塑性变形,煤柱体外侧塑性区产生水平位移,顶板下沉对巷道变形影响较小。煤柱外边缘以里3 m是最合理的断顶卸压位置。

In order to study the effect of the roof cutting position on pressure unloading and the stability of inclined coal seam,geomechanical modeling tests were carried out according to the conditions existing in the working face of Shuangyashan coal mine. Analog materials and model frames were used to simulate the geological structure and the in-situ stress of coal seam. The deformation fields of the coal pillar,coal body and roof before and after the roof cutting were measured in real time by using the digital image correlation method. The experimental study shows that when the roof cutting is carried out at the coal pillar adjacent to the roadway,deformation is concentrated in the roadway and the coal pillar,the overlying strata sank,the tension deformation occurrs in the coal pillar,that when the roof cutting is carried out at the coal pillar adjacent to the goaf,the coarse sandstone and the fine sandstone slid relatively along the boundary interface,but the sliding displacement is small,that when the roof cutting is carried out at a position having a distance of 3 meters to the outer edge of the coal pillar,the coal body on the side of the goaf is plastically deformed,the lateral plastic zone of the coal pillar will have a horizontal displacement,and the roof subsidence will have a little effect on the deformation of the coal pillar,and that the position having a distance of 3 meters to the outer edge of the coal pillar is the best roof cutting position.