双层岩梁组合结构研究
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摘要
采场覆岩具有显著的梁的结构特征,研究岩梁及组合结构的受力变形、破坏规律是采场覆岩结构研究的基础。
本文采用相似材料模拟实验和理论分析方法对单层及双层岩梁在自重作用下的破断规律及岩梁间的力学作用关系进行了研究,主要内容包括:构建岩梁相似材料模拟实验系统;选择合适的相似模拟材料并确定材料配比;进行试样的物理力学参数测定;对单层岩梁试件进行实验;对不同组合情况的双层岩梁组合结构进行实验并对实验结果进行理论分析;对实验模型进行数值模拟。
单层岩梁实验结果与材料力学公式计算结果吻合度较高,表明所选相似材料制作的岩梁试件符合材料力学中梁的要求,可用材料力学分析方法进行分析。
双层岩梁组合结构实验及其理论分析结果表明,双层梁的组合结构因组合方式不同而不同:上硬下软无粘结的情况下,层间无力的作用,各层独自运动,垮距同单层岩梁垮距一致;上硬下软弱粘结的情况下,在一定跨距内,交界面处的剪应力小于抗剪强度,双层岩梁按组合梁形式整体运动,超过该跨距后,交界面处的剪应力大于抗剪强度,组合梁遭到破坏,离层逐步发展,各层独自运动直至垮落,各层垮距同单层岩梁垮距基本一致;上硬下软强粘结的情况下,双层岩梁按组合梁结构运动直至垮落,垮距由各层试件力学性质决定。上软下硬的情况下,上部岩梁给下部岩梁加载,但载荷并不是其全部重量,而只是其中一部分,载荷大小取决于上、下岩梁的厚度、容重及弹性模量。对于上述情况均给出了表征岩梁间力学作用的计算式。
利用FLAC~(3D)数值模拟软件对单层及不同组合情下的双层岩梁随跨距增大过程中变形、破坏规律及岩层间的力学作用关系进行了模拟,数值模拟结果同相似材料模拟实验结果以及理论计算结果基本一致。
A significant beam structure exists in the stope overlying stratified rock. So the analysis of stresses and deformation failure of the beam and composite structure is the foundation of research of overlying strata’s structure.
By similar materials simulation experiment and theoretical analysis, rock beam’s breaking rule under deadweight and the mechanical interaction between rock beams in different combination conditions were studied. The main contents are listed below. Constructed the system of rock beam similar material simulation experiment. Selected the appropriate materials and determined the ratio of the experimental. Measured the physical and mechanical parameters of the specimen. Conducted breaking experiments of single rock beam with different materials and analyze the experimental results by theory. Conducted breaking experiments of double-layer rock beams in different combination conditions and analyzed the experimental results by theory. Conducted numerical simulation about rock beams’breaking experiments.
The results got from single rock beams’breaking experiment agreed with the theoretical results, indicated that rock specimens made from selected material lined with the requirements of Mechanics of Materials, analyze the experiment results of selected material by theory of mechanics of materials was suitable.
Through double-layer rock beams’breaking experiment and theoretical analysis, such conclusions were got as below. The interlaminar shear strength determine the composite structure’s formation. In the combination of top-hard-bottom-soft with no cementation between two layers, there is no mechanical interaction between rock beams, the two layers move respectively and have the same broken span as single beam. In the combination of top-hard-bottom-soft with weak cementation between two layers, shear stress at the interface is less than the interlaminar shear strength within a certain span, the two layers combined to a composite structure and move together, surpass the span, shear stress at the interface become greater than the interlaminar shear strength, the composite structure is broken, the two layers separate from each other and move respectively until broken and have the same broken span as single beam. In the combination of top-hard-bottom-soft with strong cementation between two layers, the two layers combined to a composite structure and move together till broken, the broken span is affected by mechanical properties of specimens. In the combination of top-soft-bottom-hard, the top layer load to the bottom, but the load is a part not all of the deadweight of the top layer, it is determined by thickness, density and elastic modulus of the two layers. Mechanical formulas are concluded for each condition to introduce mechanics interaction between rock beams.
By FLAC~(3D) numerical simulation software, deformation and failure law of single rock beam and the mechanics relationship between rock beams were simulated, numerical simulation results of rock specimen breaking experiment are the same as similar material simulation results.
本文采用相似材料模拟实验和理论分析方法对单层及双层岩梁在自重作用下的破断规律及岩梁间的力学作用关系进行了研究,主要内容包括:构建岩梁相似材料模拟实验系统;选择合适的相似模拟材料并确定材料配比;进行试样的物理力学参数测定;对单层岩梁试件进行实验;对不同组合情况的双层岩梁组合结构进行实验并对实验结果进行理论分析;对实验模型进行数值模拟。
单层岩梁实验结果与材料力学公式计算结果吻合度较高,表明所选相似材料制作的岩梁试件符合材料力学中梁的要求,可用材料力学分析方法进行分析。
双层岩梁组合结构实验及其理论分析结果表明,双层梁的组合结构因组合方式不同而不同:上硬下软无粘结的情况下,层间无力的作用,各层独自运动,垮距同单层岩梁垮距一致;上硬下软弱粘结的情况下,在一定跨距内,交界面处的剪应力小于抗剪强度,双层岩梁按组合梁形式整体运动,超过该跨距后,交界面处的剪应力大于抗剪强度,组合梁遭到破坏,离层逐步发展,各层独自运动直至垮落,各层垮距同单层岩梁垮距基本一致;上硬下软强粘结的情况下,双层岩梁按组合梁结构运动直至垮落,垮距由各层试件力学性质决定。上软下硬的情况下,上部岩梁给下部岩梁加载,但载荷并不是其全部重量,而只是其中一部分,载荷大小取决于上、下岩梁的厚度、容重及弹性模量。对于上述情况均给出了表征岩梁间力学作用的计算式。
利用FLAC~(3D)数值模拟软件对单层及不同组合情下的双层岩梁随跨距增大过程中变形、破坏规律及岩层间的力学作用关系进行了模拟,数值模拟结果同相似材料模拟实验结果以及理论计算结果基本一致。
A significant beam structure exists in the stope overlying stratified rock. So the analysis of stresses and deformation failure of the beam and composite structure is the foundation of research of overlying strata’s structure.
By similar materials simulation experiment and theoretical analysis, rock beam’s breaking rule under deadweight and the mechanical interaction between rock beams in different combination conditions were studied. The main contents are listed below. Constructed the system of rock beam similar material simulation experiment. Selected the appropriate materials and determined the ratio of the experimental. Measured the physical and mechanical parameters of the specimen. Conducted breaking experiments of single rock beam with different materials and analyze the experimental results by theory. Conducted breaking experiments of double-layer rock beams in different combination conditions and analyzed the experimental results by theory. Conducted numerical simulation about rock beams’breaking experiments.
The results got from single rock beams’breaking experiment agreed with the theoretical results, indicated that rock specimens made from selected material lined with the requirements of Mechanics of Materials, analyze the experiment results of selected material by theory of mechanics of materials was suitable.
Through double-layer rock beams’breaking experiment and theoretical analysis, such conclusions were got as below. The interlaminar shear strength determine the composite structure’s formation. In the combination of top-hard-bottom-soft with no cementation between two layers, there is no mechanical interaction between rock beams, the two layers move respectively and have the same broken span as single beam. In the combination of top-hard-bottom-soft with weak cementation between two layers, shear stress at the interface is less than the interlaminar shear strength within a certain span, the two layers combined to a composite structure and move together, surpass the span, shear stress at the interface become greater than the interlaminar shear strength, the composite structure is broken, the two layers separate from each other and move respectively until broken and have the same broken span as single beam. In the combination of top-hard-bottom-soft with strong cementation between two layers, the two layers combined to a composite structure and move together till broken, the broken span is affected by mechanical properties of specimens. In the combination of top-soft-bottom-hard, the top layer load to the bottom, but the load is a part not all of the deadweight of the top layer, it is determined by thickness, density and elastic modulus of the two layers. Mechanical formulas are concluded for each condition to introduce mechanics interaction between rock beams.
By FLAC~(3D) numerical simulation software, deformation and failure law of single rock beam and the mechanics relationship between rock beams were simulated, numerical simulation results of rock specimen breaking experiment are the same as similar material simulation results.
引文
[1]宁小亮,张恩强.岩梁的材料力学解与弹性力学差分解的比较分析[J].第十届全国岩石力学与工程学术大会论文集,2008: 285~289.
[2]司荣军,汪华君,岳强.采场围岩控制理论与实践综述及展望[J].矿业工程,2006,4(4): 26~27.
[3]钱鸣高.20年来采场围岩控制理论与实践的回顾[J].中国矿业大学大学学报,2000,29(1): 1~4.
[4]史红,姜福兴.采场上覆岩层结构理论及其新进展[J].山东科技大学学报,2005,24(1): 21~25.
[5]刘海明.煤矿开采造成地面沉陷的主要形式及其防治策略[J].中国煤炭,2010,(S1): 69~73.
[6]缪协兴,钱鸣高.采矿工程中存在的力学难题[J].力学实践,1995,17(5): 70~71.
[7]任德惠.井工开采矿山压力与控制[M].重庆:重庆大学出版社,1990.
[8]钱鸣高,石平五.矿山压力与控制[M].徐州:中国矿业大学出版社,2003.
[9]邹熹正.对压力拱假说的新解释[J].矿山压力与顶板管理,1989,(01):67~68.
[10]邹熹正.矿山压力与岩层控制[M].徐州:中国矿业大学出版社,2005.
[11]钱鸣高,刘听成.矿山压力及控制[M].北京:煤炭工业出版社,1984.
[12]缪协兴,钱鸣高.采场围岩整体结构与砌体梁力学模型[J].矿山压力与顶板管理,1995(3):3~12.
[13]钱鸣高,缪协兴.采场上覆岩层结构的形态及受力分析[J].岩石力学与工程学报,1995(2):97~105.
[14]钱鸣高,缪协兴,何富连.采场砌体梁结构的关键块分析[J].煤炭学报,1994,19(6):557~563.
[15]宋振骐.实用矿山压力理论[M].徐州:中国矿业大学出版社,1988.
[16] Adler L.Evaluating double elasticity in drill cores under flexure[J].Int J Rock Mech MinSci&Geomech Abstr,1970,7:357~370.
[17] Perkins T K,Krech W W.The energy balance concept of hydraulic fracturing[J].Society of Petroleum Engineers Journal,1968,8(1):1～l2
[18] Haimson B C,Tharp T M.Stress around boreholes in bilinear elastic rock[J].Society of Petroleum Engineers Joumal,1974,14:145～151.
[19] Hawkes I,Mellor M,Gariepy S.Deformation of rocks under uniaxial tension[J].Int J Rock Mech Min Sci&Geomech Abstr,1973,10:493～507
[20] Stimpson B,Rui Chen.Measurement of rock elastic moduli in tension and in compression and its practical significance[J].Canadian Geotechnical Journal,1993,30:338～347
[21]耶格J C,库克N G W.岩石力学基础[M].中国科学院工程力学研究所译.北京:科学出版社,1981.
[22]宁小亮.岩梁的变形破坏规律研究:[学位论文].西安:西安科技大学,2008.
[23]惠双琳.岩梁变形破坏模拟实验研究:[学位论文].西安:西安科技大学,2010.
[24]钱鸣高,缪协兴,许家林.岩层控制中的关键层理论研究[J].煤炭学报,1996,21(3):225~230.
[25]钱鸣高,茅献彪,缪协兴.采场覆岩中关键层上载荷的变化规律[J].煤炭学报,1998,23(2):135~139.
[26]钱鸣高,缪协兴,许家林等.岩层控制的关键层理论[M].徐州:中国矿业大学出版社,2000.
[27]梁运培.采场覆岩移动的组合岩梁理论[J].地下空间,2001,21(5):341～345
[28]刘清.组合结构设计原理[M].重庆:重庆大学出版社,2002.
[29]夏冬桃.组合结构设计原理[M].武汉:武汉大学出版社,2009.
[30] N.M.Hawkins.The Bearing Strength of Concrete Loaded Trough Rigid Plates.[J].Magiazine of concrete Research.1968.
[31] Minami K.Beam to Column Stress Transfer in Composite Structures [J].Architectural Institute of Japan.1975(3):144～145.
[32]刘长武,郭永峰,姚精明.采矿相似模拟试验技术的发展与问题[J] .中国矿业,2003,12(8):6~8.
[33]左宝成,陈从新,刘才华,沈强,肖国峰,刘晓巍.相似材料试验研究[J].岩土力学,2004,25(11):1805~1808.
[34]吴钰应,王世远,关玉顺,刘伟.相似材料配比研究[J] .辽宁工程技术大学报,1981,1:32~49.
[35]林韵梅.实验岩石力学模拟研究[M].北京:煤炭工业出版社,1989.
[36]王其一.应变片粘贴中的几个问题[J].铁道机车车辆工人, 1996,(09):8~9.
[37]张羽强,黄庆享,严茂荣.采矿工程相似材料模拟技术的发展及问题[J].煤炭技术, 2008,27(1):1~4.
[38]工程岩体试验方法标准GB_T50266-99[S].1999.
[39]白占平,曹兰柱,白润才.相似材料配比的正交试验研究[J].露天采煤技术,1996,3:22~23.
[40]刘鸿文.材料力学[M].北京:高等教育出版社,2004.
[41]李天.组合结构设计原理[M].郑州:郑州大学出版社,2010.
[42]彭文斌. FLAC3D实用教程[M].北京:机械工业出版社,2008.
[43] Itasca Consulting Group,Inc..Fast Language Analysis of continua in 3 dimensions,21·1version3.0,user’s manual.Itasca Consulting Group,Inc.,2005.
[44]陈育民,徐鼎平.FLAC/FALAC3D基础与工程实例[M].北京:中国水利水电出版社,2009.
[45]刘波,韩彦辉(美国).Flae原理、实例与应用指南[M].北京:人民交通出版社,2005.
[2]司荣军,汪华君,岳强.采场围岩控制理论与实践综述及展望[J].矿业工程,2006,4(4): 26~27.
[3]钱鸣高.20年来采场围岩控制理论与实践的回顾[J].中国矿业大学大学学报,2000,29(1): 1~4.
[4]史红,姜福兴.采场上覆岩层结构理论及其新进展[J].山东科技大学学报,2005,24(1): 21~25.
[5]刘海明.煤矿开采造成地面沉陷的主要形式及其防治策略[J].中国煤炭,2010,(S1): 69~73.
[6]缪协兴,钱鸣高.采矿工程中存在的力学难题[J].力学实践,1995,17(5): 70~71.
[7]任德惠.井工开采矿山压力与控制[M].重庆:重庆大学出版社,1990.
[8]钱鸣高,石平五.矿山压力与控制[M].徐州:中国矿业大学出版社,2003.
[9]邹熹正.对压力拱假说的新解释[J].矿山压力与顶板管理,1989,(01):67~68.
[10]邹熹正.矿山压力与岩层控制[M].徐州:中国矿业大学出版社,2005.
[11]钱鸣高,刘听成.矿山压力及控制[M].北京:煤炭工业出版社,1984.
[12]缪协兴,钱鸣高.采场围岩整体结构与砌体梁力学模型[J].矿山压力与顶板管理,1995(3):3~12.
[13]钱鸣高,缪协兴.采场上覆岩层结构的形态及受力分析[J].岩石力学与工程学报,1995(2):97~105.
[14]钱鸣高,缪协兴,何富连.采场砌体梁结构的关键块分析[J].煤炭学报,1994,19(6):557~563.
[15]宋振骐.实用矿山压力理论[M].徐州:中国矿业大学出版社,1988.
[16] Adler L.Evaluating double elasticity in drill cores under flexure[J].Int J Rock Mech MinSci&Geomech Abstr,1970,7:357~370.
[17] Perkins T K,Krech W W.The energy balance concept of hydraulic fracturing[J].Society of Petroleum Engineers Journal,1968,8(1):1～l2
[18] Haimson B C,Tharp T M.Stress around boreholes in bilinear elastic rock[J].Society of Petroleum Engineers Joumal,1974,14:145～151.
[19] Hawkes I,Mellor M,Gariepy S.Deformation of rocks under uniaxial tension[J].Int J Rock Mech Min Sci&Geomech Abstr,1973,10:493～507
[20] Stimpson B,Rui Chen.Measurement of rock elastic moduli in tension and in compression and its practical significance[J].Canadian Geotechnical Journal,1993,30:338～347
[21]耶格J C,库克N G W.岩石力学基础[M].中国科学院工程力学研究所译.北京:科学出版社,1981.
[22]宁小亮.岩梁的变形破坏规律研究:[学位论文].西安:西安科技大学,2008.
[23]惠双琳.岩梁变形破坏模拟实验研究:[学位论文].西安:西安科技大学,2010.
[24]钱鸣高,缪协兴,许家林.岩层控制中的关键层理论研究[J].煤炭学报,1996,21(3):225~230.
[25]钱鸣高,茅献彪,缪协兴.采场覆岩中关键层上载荷的变化规律[J].煤炭学报,1998,23(2):135~139.
[26]钱鸣高,缪协兴,许家林等.岩层控制的关键层理论[M].徐州:中国矿业大学出版社,2000.
[27]梁运培.采场覆岩移动的组合岩梁理论[J].地下空间,2001,21(5):341～345
[28]刘清.组合结构设计原理[M].重庆:重庆大学出版社,2002.
[29]夏冬桃.组合结构设计原理[M].武汉:武汉大学出版社,2009.
[30] N.M.Hawkins.The Bearing Strength of Concrete Loaded Trough Rigid Plates.[J].Magiazine of concrete Research.1968.
[31] Minami K.Beam to Column Stress Transfer in Composite Structures [J].Architectural Institute of Japan.1975(3):144～145.
[32]刘长武,郭永峰,姚精明.采矿相似模拟试验技术的发展与问题[J] .中国矿业,2003,12(8):6~8.
[33]左宝成,陈从新,刘才华,沈强,肖国峰,刘晓巍.相似材料试验研究[J].岩土力学,2004,25(11):1805~1808.
[34]吴钰应,王世远,关玉顺,刘伟.相似材料配比研究[J] .辽宁工程技术大学报,1981,1:32~49.
[35]林韵梅.实验岩石力学模拟研究[M].北京:煤炭工业出版社,1989.
[36]王其一.应变片粘贴中的几个问题[J].铁道机车车辆工人, 1996,(09):8~9.
[37]张羽强,黄庆享,严茂荣.采矿工程相似材料模拟技术的发展及问题[J].煤炭技术, 2008,27(1):1~4.
[38]工程岩体试验方法标准GB_T50266-99[S].1999.
[39]白占平,曹兰柱,白润才.相似材料配比的正交试验研究[J].露天采煤技术,1996,3:22~23.
[40]刘鸿文.材料力学[M].北京:高等教育出版社,2004.
[41]李天.组合结构设计原理[M].郑州:郑州大学出版社,2010.
[42]彭文斌. FLAC3D实用教程[M].北京:机械工业出版社,2008.
[43] Itasca Consulting Group,Inc..Fast Language Analysis of continua in 3 dimensions,21·1version3.0,user’s manual.Itasca Consulting Group,Inc.,2005.
[44]陈育民,徐鼎平.FLAC/FALAC3D基础与工程实例[M].北京:中国水利水电出版社,2009.
[45]刘波,韩彦辉(美国).Flae原理、实例与应用指南[M].北京:人民交通出版社,2005.