煤矿地下水库岩体碎胀特性试验研究
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摘要
鉴于岩石碎胀特性对于煤矿地下水库储水能力及地表沉陷的重要影响,选取神东矿区某矿22615面为工程背景,利用相似材料模型试验探究采空区垮落岩体应力及碎胀系数分布规律,明确垮落岩体应力-碎胀系数关系,并通过岩石压实试验进行验证,揭示饱水岩石压实特性。研究结果表明:沿采空区走向,边界附近老顶悬臂梁结构限制覆岩下沉,垮落岩体应力最低仅为0.32 MPa,碎胀系数最大达1.48;中间区域老顶结构失稳覆岩完全下沉,垮落岩体应力趋于1.5 MPa,碎胀系数降至1.09。沿采空区垂向,垮落岩体应力随高度负相关改变,而碎胀系数成正相关变化。无论沿采空区走向或垂向,垮落岩体碎胀系数与应力均满足负对数关系。与自然岩石相比,受载饱水岩石碎胀系数减幅更为明显,两者相差8.514%,为煤矿地下水库储水量和地表沉降量预测提供了基础理论依据。
Given that rock bulking is of great significance to water storage capacity and ground surface subsidence of coal mine underground reservoir, the 22615 working face in one mine of Shendong coalfield was selected as the engineering background. The stress and the bulking coefficient distribution laws of caving rock in goaf were analyzed by using the similar material model test, and then the stress-bulking coefficient relation of caving rock was established, which was verified by rock compaction experiment. Moreover, the compaction characteristic of saturated rock was revealed. The results show that: along goaf advancing direction, overlying strata subsidence is limited by the structures of cantilever beam near the boundary where the stress of caving rock is relatively low(0.32 MPa), and the corresponded maximum bulking coefficient reaches 1.48. Due to the instability of main roof structure, caving rock is compacted by overlying strata in the middle area, rock stress trends toward 1.5 MPa, while bulking coefficient reduces to 1.09. It is clear that the height exhibits a negative correlation with caving rock stress but a positive correlation with bulking coefficient in goaf vertical direction. There is a negative logarithmic relationship between stress and bulking coefficient of caving rock along either advancing direction or vertical direction. By comparing with natural rock, the bulking coefficient damping of saturated rock shows obviously under loading, which has a difference of 8.514%. This study provides a theoretical basis for water storage capacity and ground surface subsidence predictions of coal mine underground reservoir.
Given that rock bulking is of great significance to water storage capacity and ground surface subsidence of coal mine underground reservoir, the 22615 working face in one mine of Shendong coalfield was selected as the engineering background. The stress and the bulking coefficient distribution laws of caving rock in goaf were analyzed by using the similar material model test, and then the stress-bulking coefficient relation of caving rock was established, which was verified by rock compaction experiment. Moreover, the compaction characteristic of saturated rock was revealed. The results show that: along goaf advancing direction, overlying strata subsidence is limited by the structures of cantilever beam near the boundary where the stress of caving rock is relatively low(0.32 MPa), and the corresponded maximum bulking coefficient reaches 1.48. Due to the instability of main roof structure, caving rock is compacted by overlying strata in the middle area, rock stress trends toward 1.5 MPa, while bulking coefficient reduces to 1.09. It is clear that the height exhibits a negative correlation with caving rock stress but a positive correlation with bulking coefficient in goaf vertical direction. There is a negative logarithmic relationship between stress and bulking coefficient of caving rock along either advancing direction or vertical direction. By comparing with natural rock, the bulking coefficient damping of saturated rock shows obviously under loading, which has a difference of 8.514%. This study provides a theoretical basis for water storage capacity and ground surface subsidence predictions of coal mine underground reservoir.
引文
[1]范钢伟,张东升,马立强.神东矿区浅埋煤层开采覆岩移动与裂隙分布特征[J].中国矿业大学学报,2011,40(2):196-201.FAN Gang-wei,ZHANG Dong-sheng,MA Li-qiang.Overburden movement and fracture distribution induced by longwall mining of the shallow coal seam in the Shendong coalfield[J].Journal of China University of Mining&Technology,2011,40(2):196-201.
[2]李涛,李文平,孙亚军.半干旱矿区近浅埋煤层开采潜水位恢复预测[J].中国矿业大学学报,2011,40(6):894-900.LI Tao,LI Wen-ping,SUN Ya-jun.Prediction of groundwater table recovery affected by approximate shallow buried coal mining in semiarid region[J].Journal of China University of Mining&Technology,2011,40(6):894-900.
[3]赵雁海,宋选民.浅埋超长工作面裂隙梁铰拱结构稳定性分析及数值模拟研究[J].岩土力学,2016,37(1):203-209.ZHAO Yan-hai,SONG Xuan-min.Stability analysis and numerical simulation of hinged arch structure for fractured beam in super-long mining workface under shallow seam[J].Rock and Soil Mechanics,2016,37(1):203-209.
[4]顾大钊.煤矿地下水库理论框架和技术体系[J].煤炭学报,2015,40(2):239-246.GU Da-zhao.Theory framework and technological system of coal mine underground reservoir[J].Journal of China Coal Society,2015,40(2):239-246.
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[9]李连崇,唐春安,梁正召.考虑岩体碎胀效应的采场覆岩冒落规律研究[J].岩土工程,2010,31(11):3537-3541.LI Lian-chong,TANG Chun-an,LIANG Zheng-zhao.Investigation on overburden strata collapse around coal face considering effect of broken expansion of rock[J].Rock and Soil Mechanics,2010,31(11):3537-3541.
[10]王永胜,于晓波.采空区孔隙率分布模型[J].煤矿安全,2013,44(8):11-13.WANG Yong-sheng,YU Xiao-bo.A model for estimating porosity distribution in gob area[J].Safety in Coal Mines,2013,44(8):11-13.
[11]张春,题正义,李宗祥.采空区孔隙率的空间立体分析研究[J].长江科学研究院院报,2012,29(6):52-57.ZHANG Chun,TI Zheng-yi,LI Zong-xiang.Porosity of goaf in three dimensions[J].Journal of Yangtze River Scientific Research Institute,2012,29(6):52-57.
[12]王作宇,刘鸿泉.采空区应力、覆岩移动规律与顶底板岩体应力效应的一致性[J].煤矿开采,1993,(1):38-44.WANG Zuo-yu,LIU Hong-quan.Consistency between stress in goaf area,movement law of overlying strata and stress effect of roof and floor rock[J].Coal Mining Technology,1993,(1):38-44.
[13]汪北方,梁冰,孙可明,等.典型浅埋煤层长壁开采覆岩采动响应与控制研究[J].岩土力学,2017,38(9):2693-2700.WANG Bei-fang,LIANG Bing,SUN Ke-ming,et al.Research on overlying strata response and control during typical shallow coal seam longwall mining[J].Rock and Soil Mechanics,2017,38(9):2693-2700.
[14]张镇.薄基岩浅埋采场上覆岩层运动规律研究与应用[D].青岛:山东科技大学,2007.ZHANG Zhen.Study and application on overburden moving law of shallow stope in thin bedrock[D].Qingdao:Shandong University of Science and Technology,2007.
[15]杨宝贵,王俊涛,宋晓波,等.近浅埋厚煤层综放开采覆岩运移规律相似模拟研究[J].煤矿开采,2012,17(6):75-78.YANG Bao-gui,WANG Jun-tao,SONG Xiao-bo,et al.Analogue simulation for overlying strata movement rule in full mechanized caving mining shallow buried thick coal seam[J].Coal Mining Technology,2012,17(6):75-78.
[16]张冬至,邓喀中,周鸣.采动岩体碎胀系数变化规律研究[J].江苏煤炭,1998,(1):5-7.ZHANG Dong-zhi,DENG Ka-zhong,ZHOU Ming.Study on change law of rock broken expand coefficient during mining[J].Jiangsu Coal,1998,(1):5-7.
[17]张俊英.采动破碎岩体的动态碎胀性物理模拟的研究[J].选煤技术,2006,(增刊):69-72.ZHANG Jun-ying.Study of the mining-induced dynamic expansion of fractured rock mass through physical simulation[J].Coal Preparation Technology,2006,(Supp.):69-72.
[18]苏承东,顾明,唐旭,等.煤层顶板破碎岩石压实特征的试验研究[J].岩石力学与工程学报,2012,31(1):18-26.SU Cheng-dong,GU Ming,TANG Xu,et al.Experiment study of compaction characteristics of crushed stones from coal seam roof[J].Chinese Journal of Rock Mechanics and Engineering,2012,31(1):18-26.
[2]李涛,李文平,孙亚军.半干旱矿区近浅埋煤层开采潜水位恢复预测[J].中国矿业大学学报,2011,40(6):894-900.LI Tao,LI Wen-ping,SUN Ya-jun.Prediction of groundwater table recovery affected by approximate shallow buried coal mining in semiarid region[J].Journal of China University of Mining&Technology,2011,40(6):894-900.
[3]赵雁海,宋选民.浅埋超长工作面裂隙梁铰拱结构稳定性分析及数值模拟研究[J].岩土力学,2016,37(1):203-209.ZHAO Yan-hai,SONG Xuan-min.Stability analysis and numerical simulation of hinged arch structure for fractured beam in super-long mining workface under shallow seam[J].Rock and Soil Mechanics,2016,37(1):203-209.
[4]顾大钊.煤矿地下水库理论框架和技术体系[J].煤炭学报,2015,40(2):239-246.GU Da-zhao.Theory framework and technological system of coal mine underground reservoir[J].Journal of China Coal Society,2015,40(2):239-246.
[5]JANACH W.The role of bulking in brittle failure of rocks under rapid compression[J].International Journal of Rock Mechanics and Mining Sciences,1976,13(6):177-186.
[6]LAMA R D,VUTUKURI V S.Handbook on mechanical properties of rocks[M].Clausthal,Germany:Trans.Tech.Publications,1978:203-205.
[7]LEE J S,SAGONG M,CHO G C,et al.Experimental estimation of the fallout size and reinforcement design of a tunnel under excavation[J].Tunnelling and Underground Space Technology,2010,25(5):518-525.
[8]郭广礼,缪协兴,张振南.老采空区破裂岩体变形性质研究[J].科学技术与工程,2002,2(5):44-47.GUO Guang-li,MIAO Xie-xing,ZHANG Zhen-nan.Research on ruptured rock mass deformation characteristics of longwall goafs[J].Science Technology and Engineering,2002,2(5):44-47.
[9]李连崇,唐春安,梁正召.考虑岩体碎胀效应的采场覆岩冒落规律研究[J].岩土工程,2010,31(11):3537-3541.LI Lian-chong,TANG Chun-an,LIANG Zheng-zhao.Investigation on overburden strata collapse around coal face considering effect of broken expansion of rock[J].Rock and Soil Mechanics,2010,31(11):3537-3541.
[10]王永胜,于晓波.采空区孔隙率分布模型[J].煤矿安全,2013,44(8):11-13.WANG Yong-sheng,YU Xiao-bo.A model for estimating porosity distribution in gob area[J].Safety in Coal Mines,2013,44(8):11-13.
[11]张春,题正义,李宗祥.采空区孔隙率的空间立体分析研究[J].长江科学研究院院报,2012,29(6):52-57.ZHANG Chun,TI Zheng-yi,LI Zong-xiang.Porosity of goaf in three dimensions[J].Journal of Yangtze River Scientific Research Institute,2012,29(6):52-57.
[12]王作宇,刘鸿泉.采空区应力、覆岩移动规律与顶底板岩体应力效应的一致性[J].煤矿开采,1993,(1):38-44.WANG Zuo-yu,LIU Hong-quan.Consistency between stress in goaf area,movement law of overlying strata and stress effect of roof and floor rock[J].Coal Mining Technology,1993,(1):38-44.
[13]汪北方,梁冰,孙可明,等.典型浅埋煤层长壁开采覆岩采动响应与控制研究[J].岩土力学,2017,38(9):2693-2700.WANG Bei-fang,LIANG Bing,SUN Ke-ming,et al.Research on overlying strata response and control during typical shallow coal seam longwall mining[J].Rock and Soil Mechanics,2017,38(9):2693-2700.
[14]张镇.薄基岩浅埋采场上覆岩层运动规律研究与应用[D].青岛:山东科技大学,2007.ZHANG Zhen.Study and application on overburden moving law of shallow stope in thin bedrock[D].Qingdao:Shandong University of Science and Technology,2007.
[15]杨宝贵,王俊涛,宋晓波,等.近浅埋厚煤层综放开采覆岩运移规律相似模拟研究[J].煤矿开采,2012,17(6):75-78.YANG Bao-gui,WANG Jun-tao,SONG Xiao-bo,et al.Analogue simulation for overlying strata movement rule in full mechanized caving mining shallow buried thick coal seam[J].Coal Mining Technology,2012,17(6):75-78.
[16]张冬至,邓喀中,周鸣.采动岩体碎胀系数变化规律研究[J].江苏煤炭,1998,(1):5-7.ZHANG Dong-zhi,DENG Ka-zhong,ZHOU Ming.Study on change law of rock broken expand coefficient during mining[J].Jiangsu Coal,1998,(1):5-7.
[17]张俊英.采动破碎岩体的动态碎胀性物理模拟的研究[J].选煤技术,2006,(增刊):69-72.ZHANG Jun-ying.Study of the mining-induced dynamic expansion of fractured rock mass through physical simulation[J].Coal Preparation Technology,2006,(Supp.):69-72.
[18]苏承东,顾明,唐旭,等.煤层顶板破碎岩石压实特征的试验研究[J].岩石力学与工程学报,2012,31(1):18-26.SU Cheng-dong,GU Ming,TANG Xu,et al.Experiment study of compaction characteristics of crushed stones from coal seam roof[J].Chinese Journal of Rock Mechanics and Engineering,2012,31(1):18-26.