弱胶结砂质泥岩渐进性破坏力学特性试验研究
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摘要
为深入揭示弱胶结砂质泥岩渐进性破坏力学特性,对干燥与自然状态砂质泥岩试样进行渐进性破坏单轴压缩试验研究。结果表明:与硬脆性岩石相比,该类岩石裂纹密度低,自稳能力差,峰前岩石体积膨胀变形过程延长,峰后变形破坏呈现局部阶段性塑性流动特征和延时效应,渐进性变形破坏过程持续时间显著缩短;岩石弱胶结特性表现为:1峰前重要应力门槛值与峰后残余应力明显劣化;2岩石刚度与抗变形能力弱化显著;3岩石宏观破坏特征是环向剪切破坏面、张性破坏面、剪切滑移面共同作用的结果,与裂纹渐进性演化特征、层理密集程度及强度相关;4干燥状态岩样力学特性与硬脆性岩石近似相同,含水状态岩样峰前重要应力门槛值、弹性模量、峰后残余应力具有不同程度劣化,侧向膨胀变形程度提高。巷道围岩治理应加强初次支护强度并及时补强,控制围岩张拉破坏与剪切破坏,提高围岩刚度和抗变形能力。
The experimental investigations on uniaxial compression of weakly cemented sandy mudstone samples under dry and natural conditions were conducted respectively to uncover the mechanical characteristics of weakly cemented sandy mudstone.The results indicate that compared with hard and brittle rocks,such rock has some characteristics including low crack density,weak self-stability; the course of volume dilatancy deformation is prolonged at the pre-peak;the delay effect and plastic flow trait can be showed in some stages at the post-peak; and the time of progressive failure is obviously short.The weakly cemented characteristics of such rock are primarily reflected in following three aspects:( 1) the significant stress thresholds before the peak and the residual stress after the peak are obviously deteriorated;( 2) the stiffness and anti-deformation of such rock are weak conspicuously;( 3) the macroscopic failure characteristics of rock specimen are primarily result from three types of surface including tensile fracture surface,shear slip surface,and hoop shear failure surface,which have close relationship with some factors such as the crack progressive evolutionary characteristics,the density and the strength of bedding surfaces.( 4) the mechanical characteristics of weakly cemented sandy mudstone in dry condition is similar to hard and brittle rocks,while the mechanical characteristics ofsuch rock in natural condition are deteriorated in different degrees,including the important stress thresholds at prepeak,elastic modulus,the residual stress at post-peak,and the degree of lateral expansion deformation is enhanced.It is essential to strengthen the initial support strength and consolidate strength timely to keep the tensile and shear failure in control and to enhance the rigidity and anti-deformation capability of surrounding rock masses.
The experimental investigations on uniaxial compression of weakly cemented sandy mudstone samples under dry and natural conditions were conducted respectively to uncover the mechanical characteristics of weakly cemented sandy mudstone.The results indicate that compared with hard and brittle rocks,such rock has some characteristics including low crack density,weak self-stability; the course of volume dilatancy deformation is prolonged at the pre-peak;the delay effect and plastic flow trait can be showed in some stages at the post-peak; and the time of progressive failure is obviously short.The weakly cemented characteristics of such rock are primarily reflected in following three aspects:( 1) the significant stress thresholds before the peak and the residual stress after the peak are obviously deteriorated;( 2) the stiffness and anti-deformation of such rock are weak conspicuously;( 3) the macroscopic failure characteristics of rock specimen are primarily result from three types of surface including tensile fracture surface,shear slip surface,and hoop shear failure surface,which have close relationship with some factors such as the crack progressive evolutionary characteristics,the density and the strength of bedding surfaces.( 4) the mechanical characteristics of weakly cemented sandy mudstone in dry condition is similar to hard and brittle rocks,while the mechanical characteristics ofsuch rock in natural condition are deteriorated in different degrees,including the important stress thresholds at prepeak,elastic modulus,the residual stress at post-peak,and the degree of lateral expansion deformation is enhanced.It is essential to strengthen the initial support strength and consolidate strength timely to keep the tensile and shear failure in control and to enhance the rigidity and anti-deformation capability of surrounding rock masses.
引文
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[15]Pelli F,Kaiser P K,Morgenstern N R.An interpretation of ground movements recorded during construction of the Donkin-Morien tunnel[J].Canadian Geotechnical Journal,1991,28:239-254.
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[20]Eberhardt E,Stead D,Stimpson B.Quantifying progressive prepeak brittle fracture damage in rock during uniaxial compression[J].Int.J.Rock Mech Min.Sci.,1999,36(3):361-380.
[2]王渭明,赵增辉,王磊.考虑刚度和强度劣化时弱胶结软岩巷道围岩弹塑性损伤分析[J].采矿与安全工程学报,2013,30(5):680-685.Wang Weiming,Zhao Zenghui,Wang Lei,et al.Elastic-plastic damage analysis for weakly consolidated surrounding rock regarding stiffness and strength cracking[J].Journal of Mining&Safety Engineering,2013,30(5):680-685.
[3]宁建国,刘学生,谭云亮,等.浅埋煤层工作面弱胶结顶板破断结构模型研究[J].采矿与安全工程学报,2014,31(4):570-579.Ning Jianguo,Liu Xuesheng,Tan Yunliang,et al.Fracture structure model of weakly cemented roof in shallow seam[J].Journal of Mining&Safety Engineering,2014,31(4):570-579.
[4]孟庆彬,韩立军,乔卫国,等.极弱胶结地层开拓巷道围岩演化规律与监测分析[J].煤炭学报,2013,38(4):573-579.Meng Qingbin,Han Lijun,Qiao Weiguo,et al.Fracture structure model of weakly cemented roof in shallow seam[J].Journal of China Coal Society,2013,38(4):573-579.
[6]王云博,景继东,张德泉,等.弱胶结软岩巷道变形破坏控制技术及其应用[J].煤矿开采,2014,19(2):53-57.Wang Yunbo,Jing Jidong,Zhang Dequan,et al.Teconology of control deformation and failure of weakly consolidated soft-rock roadway and its application[J].Coal Mine and Technology,2014,19(2):53-57.
[7]乔卫国,韦九洲,林登阁,等.侏罗白垩纪极弱胶结软岩巷道变形破坏机理分析[J].山东科技大学学报(自然科学版),2014,35(4):1078-1083.Qiao Weiguo,Wei Jiuzhou,Ling Dengge,et al.The deformation and failure mechanism of very weakly cemented soft rock formed during Jurassic-Cretaceous period in roadway[J].Journal of Shangdong university of Science Technology(Natural Science Edition),2014,35(4):1078-1083.
[8]范明建,秦旭卫,林健,等.褐煤矿区弱胶结砂岩巷道支护技术研究[J].煤炭科学技术,2014,42(4):5-8.Fan Mingjian,Qin Xuwei,Lin Jian,et al.Study on support technology of mine roadway with weak cemented sandstone in lignite mining area[J].Coal Science and Technology,2014,42(4):5-8.
[9]姚强岭,李学华,瞿群迪,等.泥岩顶板巷道遇水冒顶机理与支护对策分析[J].采矿与安全工程学报,2011,28(1):29-33.Yao Qiangling,Li Xuehua,Qu Qundi,et al.Supporting counter-measures and roof falling mechanism reacting with water in mudstone roof roadway[J].Journal of Mining&Safety Engineering,2011,28(1):29-33.
[10]Xue Lei,Qin Siqing,Sun Qiang,et al.A study on crack damage stress thresholds of different rock types based on uniaxial compression tests[J].Rock Mechanics and Rock Engineering,2014,47(9):1183-1195.
[11]张晓平,王思敬,韩庚友,等.岩石单轴压缩条件下裂纹扩展试验研究—以片状岩石为例[J].岩石力学与工程学报,2011,30(9):1773-1781.Zhang Xiaoping,Wang Sijing,Han Gengyou,et al.Crack propagation study of rock based on uniaxial compressive test—A case study of schistose rock[J].Chinese Journal of Rock Mechanics and Engineering,2011,30(9):1773-1781.
[12]Caim,Kaiser P K,Tasakay,et al.Generalized crack initiation and crack damage stress thresholds of brittle rock masses near underground excavations[J].Journal of Rock Mechanics and Mining Sciences,2004,41(5):833-847.
[13]Diederichs M S.Rock fracture and collapse under low confinement conditions[J].Rock Mechanics and Rock Engineering,2003,36(5):339-381.
[14]Martin C D,Kaiser P K,Mccreath D R.Hoek-Bron parameters for predicting the depth of brittle failure around tunnels[J].Canadian Geotechnical Journal,1999,36:136-151.
[15]Pelli F,Kaiser P K,Morgenstern N R.An interpretation of ground movements recorded during construction of the Donkin-Morien tunnel[J].Canadian Geotechnical Journal,1991,28:239-254.
[16]Brace W F,Paulding B W,Scholz C.Dilatancy in the fracture of crystal-line rocks[J].Journal of Geophysical Research,1966,71(16):3939-3953.
[17]Bieniawski Z T.Mechanism of brittle fracture of rock,Parts I,II and III[J].International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts,1967,4(4):395-430.
[18]Martin C D,Chandler N A.The progressive fracture of Lac du Bonnet granite[J].Int.J.Rock Mech.Min.Sci.,1994,31:643-659.
[19]Wawersik W R,Fairhurst C.A study of brittle rock fracture in laboratory compression experiments[J].International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts,1970,7(5):565-575.
[20]Eberhardt E,Stead D,Stimpson B.Quantifying progressive prepeak brittle fracture damage in rock during uniaxial compression[J].Int.J.Rock Mech Min.Sci.,1999,36(3):361-380.