岩质边坡物理模型试验相似材料研究
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摘要
岩质边坡物理模型试验中相似材料的选取与制作,通常只是考虑密度、粘聚力、内摩擦角和弹性模量参数在数值上的相似关系,并未考虑相似材料是否能够再现复杂应力条件下岩石的强度和变形特性.为了解决这一问题,通过统计分析汶川地震所诱发滑坡的地层岩性,选取其中常见的石英岩和砂岩作为沉积岩原型;确定相似材料制备的主要控制指标以及试样成型方法,并分别采用两种常用的地质模型相似材料制备方法,在实验室制备其三轴压缩试验标准试样;开展两种相似材料标准试样的三轴压缩试验,研究其在不同围压条件下的应力应变特性与破坏模式.试验结果表明:不同围压条件下,实验室制备的两种相似材料标准试样在剪切破坏之前的应力应变曲线变化规律同实际的岩石原型相符,表现为线弹性关系;相似材料标准试样所受围压与其单轴抗压强度的比值不同的情况下,试样剪切破坏时所受偏应力与其单轴抗压强度的比值与实际岩石原型三轴试验中的比值相近,但相似材料试样的破坏应变均小于实际岩石原型的破坏应变.
In the selection and manufacture of similar materials for physical model tests of rock slopes,only the similarities in the magnitudes of density,cohesion,internal friction angle and elastic modulus were generally taken into consideration. The ability of the obtained similar materials to reproduce the strength and deformation behaviors of rock masses under complicated stress conditions was typically not considered. First,limestone and sandstone were herein selected as sedimentary rock prototypes, according to the stratigraphy of Wenchuan earthquake-induced landslides. After the primary control indexes and manufacturing process were determined,two common configuration methods for similar materials in geological models were used to manufacture the standard samples for triaxial compression tests. Finally,static triaxial compression tests of the standard samples were conducted to study the stress-strain behaviors and failure modes of two similar materials under various confining pressures. The experimental results indicated that, before the shear failure of standard samples, the stress-strain curves of two similar materials were observed to have a linear elastic relationship under the different confining pressures, and were in accordance with those of the actual rocks. When shear failure of standard samples occurred under different ratios of confining pressure to uniaxial compression strength,the ratios of the deviatoric stresses acting on the samples to the corresponding uniaxial compression strengths were close to those of the actual rocks,whereas the failure strains of similar materials were less than those of the actual rocks.
In the selection and manufacture of similar materials for physical model tests of rock slopes,only the similarities in the magnitudes of density,cohesion,internal friction angle and elastic modulus were generally taken into consideration. The ability of the obtained similar materials to reproduce the strength and deformation behaviors of rock masses under complicated stress conditions was typically not considered. First,limestone and sandstone were herein selected as sedimentary rock prototypes, according to the stratigraphy of Wenchuan earthquake-induced landslides. After the primary control indexes and manufacturing process were determined,two common configuration methods for similar materials in geological models were used to manufacture the standard samples for triaxial compression tests. Finally,static triaxial compression tests of the standard samples were conducted to study the stress-strain behaviors and failure modes of two similar materials under various confining pressures. The experimental results indicated that, before the shear failure of standard samples, the stress-strain curves of two similar materials were observed to have a linear elastic relationship under the different confining pressures, and were in accordance with those of the actual rocks. When shear failure of standard samples occurred under different ratios of confining pressure to uniaxial compression strength,the ratios of the deviatoric stresses acting on the samples to the corresponding uniaxial compression strengths were close to those of the actual rocks,whereas the failure strains of similar materials were less than those of the actual rocks.
引文
[1]许强,刘汉香,邹威,等.斜坡加速度动力响应特性的大型振动台试验研究[J].岩石力学与工程学报,2010,29(12):2420-2428.XU Qiang,LIU Hanxiang,ZOU Wei,et al.Largescale shaking table test study of acceleration dynamic response characteristics of slopes[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(12):2420-2428.
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[7]董金玉,杨继红,伍法权,等.顺层岩质边坡加速度响应规律和滑动堵江机制大型振动台试验研究[J].岩石力学与工程学报,2013,32(增刊2):3861-3867.DONG Jinyu,YANG Jihong,WU Faquan,et al.Large-scale shaking table test research on acceleration response rules of bedding layered rock slope and its blocking mechanism of river[J].Chinese Journal of Rock Mechanics and Engineering,2013,32(S2):3861-3867.
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[9]许强,裴向军,黄润秋,等.汶川地震大型滑坡研究[M].北京:科学出版社,2009:51-465.
[10]王汉鹏,李术才,张强勇,等.新型地质力学模型试验相似材料的研制[J].岩石力学与工程学报,2006,25(9):1842-1847.WANG Hanpeng,LI Shucai,ZHANG Qiangyong,et al.Development of a new geomechanical similar material[J].Chinese Journal of Rock Mechanics and Engineering,2006,25(9):1842-1847.
[11]BRADY B H G,BROWN E T.Rock mechanics:for underground mining[M].[S.l.]:Springer Science&Business Media,2013:101-104.
[12]HEUER R E,HENDRON JR A J.Geomechanical model study of the behavior of underground openings in rock subjected to static loads:report 1.development of modeling techniques[R].Urbana:Illinois University,1969.
[2]刘汉香,许强,徐鸿彪,等.斜坡动力变形破坏特征的振动台模型试验研究[J].岩土力学,2011,32(增刊2):334-339.LIU Hanxiang,XU Qiang,XU Hongbiao,et al.Shaking table model test on slope dynamic deformation and failure[J].Rock and Soil Mechanics,2011,32(S2):334-339.
[3]邹威,许强,刘汉香,等.强震作用下层状岩质斜坡破坏的大型振动台试验研究[J].地震工程与工程振动,2011,31(4):143-149.ZOU Wei,XU Qiang,LIU Hanxiang,et al.Largescale shaking table model test study on failure of layered rocky slope under strong ground motion[J].Journal of Earthquake Engineering and Engineering Vibration,2011,31(4):143-149.
[4]董金玉,杨国香,伍法权,等.地震作用下顺层岩质边坡动力响应和破坏模式大型振动台试验研究[J].岩土力学,2011,32(10):2977-2982.DONG Jinyu,YANG Guoxiang,WU Faquan,et al.The large-scale shaking table test study of dynamic response and failure mode of bedding rock slope under earthquake[J].Rock and Soil Mechanics,2011,32(10):2977-2982.
[5]杨国香,叶海林,伍法权,等.反倾层状结构岩质边坡动力响应特性及破坏机制振动台模型试验研究[J].岩石力学与工程学报,2012,31(11):2214-2221.YANG Guoxiang,YE Hailin,WU Faquan,et al.Shake table model test on dynamic response characteristic and failure mechanism of antidip layered rock slope[J].Chinese Journal of Rock Mechanics and Engineering,2012,31(11):2214-2221.
[6]杨国香,伍法权,董金玉,等.地震作用下岩质边坡动力响应特性及变形破坏机制研究[J].岩石力学与工程学报,2012,31(4):696-702.YANG Guoxiang,WU Faquan,DONG Jinyu,et al.Study of dynamic response characters and failure mechanism of rock slope under earthquake[J].Chinese Journal of Rock Mechanics and Engineering,2012,31(4):696-702.
[7]董金玉,杨继红,伍法权,等.顺层岩质边坡加速度响应规律和滑动堵江机制大型振动台试验研究[J].岩石力学与工程学报,2013,32(增刊2):3861-3867.DONG Jinyu,YANG Jihong,WU Faquan,et al.Large-scale shaking table test research on acceleration response rules of bedding layered rock slope and its blocking mechanism of river[J].Chinese Journal of Rock Mechanics and Engineering,2013,32(S2):3861-3867.
[8]杨长卫,张建经.双面高陡边坡的地震滑坡响应分析[J].西南交通大学学报,2013,48(3):415-422.YANG Changwei,ZHANG Jianjing.Landslide responses of high steep hill with two-side slopes under ground shaking[J].Journal of Southwest Jiaotong University,2013,48(3):415-422.
[9]许强,裴向军,黄润秋,等.汶川地震大型滑坡研究[M].北京:科学出版社,2009:51-465.
[10]王汉鹏,李术才,张强勇,等.新型地质力学模型试验相似材料的研制[J].岩石力学与工程学报,2006,25(9):1842-1847.WANG Hanpeng,LI Shucai,ZHANG Qiangyong,et al.Development of a new geomechanical similar material[J].Chinese Journal of Rock Mechanics and Engineering,2006,25(9):1842-1847.
[11]BRADY B H G,BROWN E T.Rock mechanics:for underground mining[M].[S.l.]:Springer Science&Business Media,2013:101-104.
[12]HEUER R E,HENDRON JR A J.Geomechanical model study of the behavior of underground openings in rock subjected to static loads:report 1.development of modeling techniques[R].Urbana:Illinois University,1969.