软弱层对层状复合泥岩体力学特性影响研究
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摘要
为研究软弱层对层状复合泥岩体力学性质的影响规律,有效提高层状复合泥岩体力学参数的可靠性,考虑到现场很难完整取得含软弱层的层状泥岩体试件,采取室内压制办法制作具有规则层状特征的泥岩试样,然后对其进行单轴和三轴压缩试验,对比分析各试样的强度、变形特性。试验结果表明:当软弱层厚度比变化时,层状复合泥岩体的强度、变形、弹性模量均随之发生规律性变化;上软下硬型层状泥岩与含软弱夹层层状泥岩试样的单轴抗压强度和弹性模量均随软弱层厚度的增加而非线性降低;轴向应力损失率分析表明,软弱层显著降低了硬层泥岩强度,降幅达70%以上;在三轴压缩试验条件下,层状泥岩的承载能力均有不同程度的提高。层状泥岩的粘聚力和内摩擦角随夹层厚度的增加而减小。试验结果对区域性软岩地基的设计和施工具有一定指导意义。
In order to study the influence of weak layer on the mechanical properties of stratified composite mudstone mass,and improve the reliability of the mechanical parameters of stratified composite mudstone effectively,considering the samples are not easy to be obtained by coring in field,the regularly stratified mudstone was made by pressing,and the uniaxial and triaxial compression tests were carried out in order to analyze the strength and deformation of samples. The test results show that the strength,deformation and elastic modulus of stratified composite mudstone mass changes regularly with the change of the thickness ratio of the weak layer. The uniaxial compressive strength and elastic modulus declines in nonlinear with the increase in the soft thickness ratio of upper-soft and lower-hard stratified mudstone samples. The analysis of the axial stress loss rate shows that the soft layer weakens the strength of the hard mudstone significantly. The strength decreases by more than 70%. The bearing capacity of mudstone with weak layers will be improved more or less in triaxial compression test. The cohesion and internal friction angle of stratified mudstone with weak interlayer decrease with the increase of the thickness of weak interlayer. The results could be referred for the design and construction in the soft rock area.
In order to study the influence of weak layer on the mechanical properties of stratified composite mudstone mass,and improve the reliability of the mechanical parameters of stratified composite mudstone effectively,considering the samples are not easy to be obtained by coring in field,the regularly stratified mudstone was made by pressing,and the uniaxial and triaxial compression tests were carried out in order to analyze the strength and deformation of samples. The test results show that the strength,deformation and elastic modulus of stratified composite mudstone mass changes regularly with the change of the thickness ratio of the weak layer. The uniaxial compressive strength and elastic modulus declines in nonlinear with the increase in the soft thickness ratio of upper-soft and lower-hard stratified mudstone samples. The analysis of the axial stress loss rate shows that the soft layer weakens the strength of the hard mudstone significantly. The strength decreases by more than 70%. The bearing capacity of mudstone with weak layers will be improved more or less in triaxial compression test. The cohesion and internal friction angle of stratified mudstone with weak interlayer decrease with the increase of the thickness of weak interlayer. The results could be referred for the design and construction in the soft rock area.
引文
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[19]王晓谋.考虑硬壳层作用的软土地基临塑荷载计算[J].岩土工程学报,2002,24(6):720~723.Wang Xiaomou.Calculation of proporitional limit load for soft clay foundation involving the effect of dry crust[J].Chinese Journal of Geotechnical Engineering,2002,24(6):720~723.(in Chinese)
[2]陈道松,饶文举,雷德江.新近系泥岩风化残积层力学指标研究[J].工程勘察,2015,(7):23~29.Chen Daosong,Rao Wenju,Lei Dejiang.Study on mechanical indices of Neogene mudstone weathering eluvium[J].Geotechnical Investigation&Surveying,2015,(7):23~29.(in Chinese)
[3]B.Amadei.Strength of a regularly jointed rock mass under biaxial and axisymmetric loading conditions[J].International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts,1988,25(1):3~13.
[4]Gerrard C.M.Elastic models of rock masses having one,two and three sets of joints[J].International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts,1982,19(1):15~23.
[5]Tien Y.M.,Tsao P.F..Preparation and mechanical properties of artificial transversely isotropic rock[J].Intemational Jounal of Rock Mechanics&Mining Sciences,2000,37(6):1001~1012.
[6]Tien Y.M.,Kuo M.C..A failure criterion for transversely isotropic rocks[J].International Journal of Rock Mechanics&Mining Sciences,2001,38(3):399~412.
[7]H.B.Mühlhaus,P.Hornby.Energy and averages in the mechanics of granular materials[J].Tectonophysics,2001,335(1/2):63~80.
[8]徐素国,梁卫国,莫江等.软弱泥岩夹层对层状盐岩体力学特性影响研究[J].地下空间与工程学报,2009,5(5):878~883.Xu Suguo,Liang Weiguo,Mo Jiang et al.Influence of weak mudstone intercalated layer on mechanical properties of lam inated salt rock[J].Chinese Journal of Underground Space and Engineering,2009,5(5):878~883.(in Chinese)
[9]李银平,刘江,杨春和.泥岩夹层对盐岩变形和破损特征的影响分析[J].岩石力学与工程学报,2006,25(12):2461~2466.Li Yinping,Liu Jiang,Yang Chunhe.Influence of mudstone interlayer on deformation and failure characteristics of salt rock[J].Chinese Journal of Rock Mechanics and Engineering,2006,25(12):2461~2466.(in Chinese)
[10]曹林卫,彭向和,任中俊等.三轴压缩下层状盐岩体细观损伤本构模型[J].岩石力学与工程学报,2010,29(11):2304~2311.Cao Linwei,Peng Xianghe,Ren Zhongjun et al.Mesoscopic damage constitutive model of bedded salt rock mass under triaxial compression[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(11):2304~2311.(in Chinese)
[11]姜德义,任涛,陈结等.含软弱夹层盐岩型盐力学特性试验研究[J].岩石力学与工程学报,2012,31(9):1797~1803.Jiang Deyi,Ren Tao,Chen Jie et al.Experimental study of mechanical characteristics of molded salt rock with weak interlayer[J].Chinese Journal of Rock Mechanics and Engineering,2012,31(9):1797~1803.(in Chinese)
[12]王安明,杨春和,黄诚等.层状盐岩力学和变形特性数值试验研究[J].岩土力学,2009,30(7):2173~2178.Wang Anming,Yang Chunhe,Huang Cheng et al.Numerical experiment study of deformation and mechanical properties of layered salt rock[J].Rock and Soil Mechanics,2009,30(7):2173~2178.(in Chinese)
[13]李林,陈结,姜德义等.单轴条件下层状盐岩的表面裂纹扩展分析[J].岩土力学,2011,32(5):1394~1398.Li Lin,Chen Jie,Jiang Deyi et al.Analysis of surface crack growth in layered salt rock under uniaxial compression[J].Rock and Soil Mechanics,2011,32(5):1394~1398.(in Chinese)
[14]李荣伟.浅埋泥岩水工隧洞变形特征及主要工程地质问题[J].工程勘察,2014,(11):24~28.Li Rongwei.Deformation characteristics of shallow buried mudstone tunnel and the main engineering geological problems[J].Geotechnical Investigation&Surveying,2014,(11):24~28.(in Chinese)
[15]张顶立,王悦汉,曲天智.夹层对层状岩体稳定性的影响分析[J].岩石力学与工程学报,2000,19(2):140~144.Zhang Dingli,Wang Yuehan,Qu Tianzhi.Influence analysis of interband on stability of stratified rock mass[J].Chinese Journal of Rock Mechanics and Engineering,2000,19(2):140~144.(in Chinese)
[16]周火明,盛谦,陈殊伟等.层状复合岩体变形试验尺寸效应的数值模拟[J].岩石力学与工程学报,2004,23(2):289~292.Zhou Huoming,Sheng Qian,Chen Shuwei et al.Numerical simulation on size-effect in deformation test of layer composite rockmass[J].Chinese Journal of Rock Mechanics and Engineering,2004,23(2):289~292.(in Chinese)
[17]贾善坡,罗金泽,吴渤等.层状岩体单轴压缩破损特征与数值模拟研究[J].郑州大学学报(工学版),2014,35(5):69~73.Jia Shanpo,Luo Jinze,Wu Bo et al.Experimental study on the behavior of concrete filled steel tubes with concrete block subjected to axial load[J].Journal of Zhengzhou University(Engineering Science),2014,35(5):69~73.(in Chinese)
[18]左双英,叶明亮,唐晓玲等.层状岩体地下洞室破坏模式数值模型及验证[J].岩土力学,2013,34(S1):458~465.Zuo Shuangying,Ye Mingliang,Tang Xiaoling et al.Numerical modle and validation of failure mode for underground caverns in layered rock mass[J].Rock and Soil Mechanics,2013,34(S1):458~465.(in Chinese)
[19]王晓谋.考虑硬壳层作用的软土地基临塑荷载计算[J].岩土工程学报,2002,24(6):720~723.Wang Xiaomou.Calculation of proporitional limit load for soft clay foundation involving the effect of dry crust[J].Chinese Journal of Geotechnical Engineering,2002,24(6):720~723.(in Chinese)