沟壑区浅埋煤层开采覆岩运动演化致灾特征

Impact of overburden movement evolution on disasters in shallowburied coal seam mining in ravine regions

为进一步研究浅埋煤层开采沟壑区覆岩运动演化致灾特征,以榆神矿区锟源煤矿113101首采工作面为工程背景,采用了数值计算和物理相似模拟实验方法,分析了沟壑区浅埋煤层开采过程中覆岩应力及位移动态演化特征、覆岩破断及裂隙发育规律,初步揭示了过沟开采灾害特征及相互作用关系,针对性提出了综合治理方法。研究结果表明:过沟开采中,沟壑顺坡段呈“受压”状态,逆坡段呈“受拉”状态,谷底位移变化量最大、逆坡段其次、顺坡段最小。二号沟壑顺坡段下部及谷底、一号沟壑逆坡段下部及谷底范围分别形成应力集中且位移量达到最大,水平应力峰值为17.4、14.5 MPa,最大位移值为1.7、1.0 m。工作面推进至沟壑区顺坡段时周期来压步距约为逆坡段的两倍,顺坡段“覆岩完整区”面积较大,载荷传递至工作面支架易造成压架现象;沟壑逆坡段区域,覆岩厚度增加,拉伸型裂隙发育明显,易导致沟体滑坡;沟壑谷底区域,顶板切落形成塌陷型裂隙,易诱发工作面压架和突水溃沙灾害。不同灾害间相互关联,沟体滑坡抑制工作面突水溃沙但促进切顶压架灾害,顶板切落压架同时促进突水溃沙和沟体滑坡灾害。根据覆岩灾害产生区域及作用特征,提出了上游截排地表水、顺坡段中上部岩层预裂、逆坡段降坡加固、谷底及逆坡段坡脚注浆等综合防治措施,为工作面安全高效回采提供相应研究基础。

In order to further investigate the impact of overburden movement evolution on disasters in shallowburied coal seam mining in ravine regions,first mining face 113101 of Kunyuan Coal Mine in Yushen Mining Area was set as the engineering background.With the aid of numerical simulation and physical modeling tests in shallowburied coal seam mining in ravine regions,the study analyzed the stress and dynamic displacement evolution of overburden,as well as the characteristics of fracture,and crack development.The disaster characteristics and relevant interaction relationship at ravinepassing process of mining were preliminary revealed,and the comprehensive controlling measure was put forward.The results showed that the downhill section of ravine was in compression state whilst the uphill section was in tension state when the ravinepassing mining were under way.Displacement at the ravine bottom was the largest,followed by the uphill section and the downhill section.The stress concentration is formed in the lower part of the downhill section and the ravine bottom of ravine No.2,the lower part of the uphill section and the ravine bottom of ravine No.1,and the displacement reaches the maximum.The peak horizontal stress is 17.4 MPa and 14.5 MPa,and the maximum displacement is 1.7 m and 1.0 m.When the working face is pushed to the downhill of the ravine area,the periodic weighting interval is about twice that of the uphill.The area of the overburden complete area in the downhill is large,and the load is transmitted to the working face support to cause the supports crushing phenomenon.Advancing to the area of uphill,the thickness of overburden rock increases,and the development of tensile cracks is obvious,which is easy to lead to ravineinduced landslide.It advances to the ravine bottom area,the roof collapses to form a collapse cracks,which is easy to induce supports crushing and watersand inrush disasters in the working face.Different disasters are interrelated,the ravineinduced landslide inhibits the watersand inrush of the working face but promotes the roof caving and supports crushing disaster.The roof caving and supports crushing also promotes the watersand inrush and the ravineinduced landslide disasters.According to the area and action characteristics of overburden disasters,the comprehensive control measures such as intercepting surface water in the upstream,presplitting the middle and upper strata in the downhill section,slope reinforcement in the uphill section,grouting reinforcement at the bottom of the ditch and the slope toe of the uphill section are put forward,which provided a corresponding research foundation for safe and efficient mining in the working face.