基于颗粒接触模型的砂土剪切波速研究
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摘要
砂土的剪切波速是一个重要的土动力学参数,它能够反映出砂土骨架的结构性,对砂土剪切波速的研究一直是土动力学及岩土工程中的核心课题。在过去的几十年中,许多学者得到了很多具有重要意义的研究成果,但是这些研究成果大多集中在宏观范畴,而对于砂土甚至所有土体的细观结构的研究逐渐成为土动力学的研究重点。本文从砂土颗粒间的接触入手,在颗粒接触理论的基础上对砂土剪切波速进行研究。
     考察分析了实际砂土颗粒的表观特征。对福建标准砂、杭州黄砂和人工石英砂进行筛分取样,从每个样本抽取一定数量的颗粒进行电镜扫描获得颗粒二维图像,计算出砂土样本颗粒性质的平均参数。砂土颗粒的粒径在0.75-2mm之间,用肉眼是无法对其颗粒表观特征进行观察的,借助于场发射电镜扫描仪,砂颗粒可以被放大几百至几万倍并形成扫描图像被记录下来。对这些图像进行数学处理可以对砂颗粒的表观特征进行定量的描述,为后续的砂颗粒间接触模型的推导提供必要的参数。
     处于不同地层深度的砂土由于自重应力、附加应力以及孔隙比(密实度)的变化而使砂土颗粒间的接触压力不同,而颗粒的表观特征的差异又会导致在接触面上的接触应力的分布形式不同。综合前人在对金属球体的接触问题上的研究成果,对砂土颗粒间的接触模型进行探讨。在砂土颗粒表观特征研究的基础上,借助理论分析或数值模拟研究砂土颗粒间真实接触面、接触应力分布在不同接触压力及粗糙度下的表达式,然后推导法向变形量、切向变形量的计算方法和表达式。在砂土颗粒接触模型的基础上推导出砂土颗粒法向接触刚度、切向接触刚度的表达式。
     在宏观上将砂土介质视为连续介质,推导出砂土的等效剪切模量和剪切波速计算公式。对颗粒间接触力、颗粒接触点数、颗粒粒径等等参数进行平均化处理,在散粒体介质的组构及本构关系研究的基础上,将砂土颗粒接触模型与砂土的宏观物理量联系起来。
     通过试验和工程实例对本文提出的计算公式或者关系式进行验证,并考察应用效果。采用弯曲元剪切波速测试仪对不同类型的砂土进行室内试验,对比其颗粒表观特征对剪切波速的影响,并对理论公式进行补充和修正。提出了一种剪切波速的简化计算方法并应用到工程中的实例中,将本文方法计算结果与实测数据对比,分析本文方法应用的可行性和效果。
Shear wave velocity of sand, which represents the structure of sand skeleton, is an important parameter in soil dynamic mechanics. Research on shear wave velocity of sand has been always one of primary problems in soil dynamic mechanics and geotechnical engineering. A lot of meaningful researches have been obtained in the past several decades, which mostly focus on macro-scope. Recently, researches on micro structures of sand turn to be more and more important in soil dynamics. In this dissertation, the contact of sand particles is taken to be the breakthrough point, and the shear wave velocity of sand is studied based on particle contact theory.
     Firstly, the surface characteristic of sand particles is analyzed. Several sand samples are made through filtration and screening of Fujian standard sand, Hangzhou sand and man-made quartz sand. Afterwards a few sand particles which are picked up randomly from every sample are scanned by electron microscope.2-D photos of sand particles obtained by scan are analyzed to calculate the average values of surface characteristic parameters of every sand sample. Diameters of sand particles are mostly ranged in 2-0.75mm, which means people can't observe sand particles with naked eyes. By using scanning electron microscope, the images of sand particles can be magnified hundreds or thousands times. Then some graphical and mathematical treatments are taken based on these images to describe the surface characteristic of sand particles, which provides some essential parameters for the deriving of sand particles contact model.
     For sands in different depths, contact forces between sand particles vary with gravity stress, additional stresses and porosity (compactness), and the distribution of contact stress is greatly influenced by surface characteristic of sand particles. According to previous researches on metal particle contacting, the contact model of sand particles is discussed. Subsequently, on the basis of research on sand particles surface characteristic, the formulas of real contact area and distribution of contact stress under different contact force and roughness are derived using theoretical analysis and numerical simulation. At the same time, the calculation method and formulas of normal deformation and shear deformation are obtained. Then, normal contact stiffness and shear contact stiffness of sand particles are derived according to researches above.
     Equivalent shear modulus and shear wave velocity are derived by considerirg sand as continuous media macroscopically. With average treatment on contact forces, contact points and particle radius, the relationships between macro parameters and contact model of sand are established according to fabric and constitutive research of granular media.
     Formulas and relationships established in this dissertation are verified by experiment and measured data, and the effect of application is also evaluated. An experimental research concerning the influence of particle surface characteristic on shear wave velocity is taken by using bender element testing equipment, which provides addition and correction to theoretical formulas above. A simplized calculation method for shear wave velocity is established which can be used to predict shear wave velocity of sand in projects. The application feasiblity and effect of this method is analyzed by comparing calculated results of simplized method with measured data.
引文
Andrus R D, Stokoe K H II. Liquefaction resistance of soils from shear-wave velocity[J]. Journal of Geotechnical and Geoenvironmental Engineering, ASCE, 2000,126(11):1015-1025.
    Bahrami M. Modeling of Thermal joint resistance for rough sphere-flat contact in a vacuum[D]. Waterloo, University of Waterloo,2004.
    Bahrami M, Yovanovich M M, Culham J R. A compact model for spherical rough contacts[J].J ournal of Tribology,2005,127:884-889.
    Berryman J G. Confirmation of Biot's theory [J]. Applied Physics Letters.1980,37: 382-384.
    Biot M A. The theory of propagation of elastic waves in a fluid-saturated porous solid: I [J]. Low-frequency range. The Journal of the Acoustical Society of America,1956,28:168-178.
    Biot M A.. The theory of propagation of elastic waves in a fluid-saturated porous solid: II [J]. Higher-frequency range. The Journal of the Acoustical Society of America, 1956,28:179-191.
    Biot M A.. Generalized theory of acoustic propagation in porous dissipative media[J]. The Journal of the Acoustical Society of America,1962,34:1254-1264.
    Bowen R M. Commpressible porous media models by use of the theory of mixtures [J]. International Journal of Engineering Science.1982,20(6):697-735.
    Bowman E T, Soga K. Drummond, T.W.. Particle shape characterisation using Fourier analysis[J]. CUED, D-soils, TR315,2000:1-20.
    Brutsaert W, Luthin J N. The velocity of sound in soils near the surface as a function of the moisture content[J]. Journal of Geophysical Research,1964,69:643-652.
    Brandt H, Habra L, Calif. A study of the speed of sound in porous granular media[J]. Journal of Applied Mechanics,1955,22:479-486.
    Changfu Wei, Kanthasamy K M. A continuum theory of porous media saturated by
    multiple immiscible fluids:I. Linear poroelasticity[J]. International Journal of Engineering Science,2002,40:1807-1833.
    Changfu Wei, Kanthasamy K M. A continuum theory of porous media saturated by multiple immiscible fluids:II. Lagrangian description and variational structure[J]. International Journal of Engineering Science,2002,40:1835-1854.
    Chen Yun-min, Zhou Yan-guo. Technique standardization of bender elements and international test[J]. ASCE Geotechnical Special Publication,2006,150:90-97.
    Cho G C, Dodds J, Santamarina J C. Particle shape effects on packing density, stiffness, and strength:Natural and crushed sands[J]. Journal of Geotechnical and Geoenvironmnetal Engineering.,2006,132(5):591-602.
    Chotiros N P. Biot model of sound propagation in water-saturated sand[J]. The Journal of the Acoustical Society of America,1995,97(1):199-214.
    Clark M W. Quantitative shape analysis:a review[J]. Mathematical Geology,1981, 13(4):303-320.
    Cundall P A, Strack O D L. A discrete numerical model for granular assembles [J]. Geotechnique,1979,29(1):47—6.
    Digby P J. The effective elastic moduli of porous granular rocks[J]. Journal of Applied Mechanics,1981,48:803-808.
    Duffy J, Mindlin R D. Stress-strain relations for a simple model of a granular medium[J]. Journal of Applied Mechanics,1957,25:402-406.
    Dutta A D, Penumadu D. Hardness and modulus of individual sand particles using nanoindentation[C]. Proceedings of Geo-Denver 2007 conference. Denver. Geotechnical Special Publication,2007.
    Greenwood J A, Tripp J H. The elastic contact of rough spheres[J]. Journal of Applied Mechanics,1967,34:153-160.
    Greenwood J A, Johnson K L, Matsubara M. A surface roughness parameter in Hertz contact[J]. Wear,1984,100:47-57.
    Ishihara K. Approximate forms of wave equations for water-saturated porous materials and related dynamic module[J]. Soils and Foundations,1970,10(4):
    10-38.
    Johnson K L. Contact mechanics[M]. Cambridge, Cambridge University Press, 1985.
    Kagami J, Yamada K, Hatazawa T. Contact between a sphere and rough plates[J]. Wear,1983,87:93-105.
    Kalker J J, Dekking F M, Vollebregt E A H. Simulation of rough, elastic contacts [J]. Journal of Applied Mechanics,1997,64:361-368.
    Krumbein W C. Measurement and geological significance of shape and roundness of sedimentary particles[J]. Journal of Sedmentary Petrology,11(2):64-72.
    Kuster G T, Toksoz M N. Velocity and auenuatiot of seismic waves in two-phase media:part 1. The recical formulations[J]. Geophysics,1974,39:587-618.
    Kuster G T, Toksoz M N. Velocity and auenuatiot of seismic waves in two-phase media: part 2. Experimental results[J]. Geophysics,1974,39(5):607-618.
    Leroueil S, Vaughan P R. The general and congruent effects of structure in natural soils and weak rocks[J]. Geotechnique,1990,40(3):467-488.
    Matsuoka H, Sakakibara K. A constitutive model for sands and clays evaluating principal stress rotation[J]. Soils and Foundations,1987,27 (4):73-88.
    Majumdar A, Tien, C. L.. Fractal characterization and simulation of rough surfaces[J]. Wear,1990,136:313-327.
    Majumdar A, Bhushan B. Role of fractal geometry in roughness characterization and contact mechanics of surfaces [J]. Journal of Tribol,1990,112:205-216.
    Majumdar A, Bhushan B. Fractal model of elastic-plastic contact between rough surfaces[J]. Journal of Tribol,1991,113:1-11.
    Mandelbrot B B. How long is the coast of Britain?statistical self-similarity and fractional dimension[J]. Science,1967,155:636-638.
    Mindlin R D. Compliance of elastic bodies in contact[J]. Journal of Applied Mechanics,1949,17:259-268.
    Murphy W F Ⅲ. Effects of partial water saturation on attenuation in Massilon sandstone and Vycor porous glass[J]. The Journal of the Acoustical Society of America,1982,71 (6):1458-1468.
    Murphy W F III. Effects of microstructure and pore fluids on the acoustic properties of granular sedimentary materials[D]. Palo Alto, Stanford University,1982.
    Nagy P B. Slow wave propagation in air-filled permeable solids[J]. The Journal of the Acoustical Society of America,1993,93(6):3224-3234.
    Ogushwitz P R. Applicability of the Biot theory, I. Low-porosity materials[J]. The Journal of the Acoustical Society of America,1985,77(2):429-440.
    Ogushwitz P R. Applicability of the Biot theory, II. Suspensions[J]. The Journal of the Acoustical Society of America,1985,77(2):441-452.
    Ogushwitz P R. Applicability of the Biot theory, III. Wave speeds versus depth in marine sediments[J]. The Journal of the Acoustical Society of America,1985, 77(2):453-464.
    Plona T J. Observation of a second bulk compressional wave at ultrasonic frequency[J]. Applied Physics Letters,1980,36(4):259-261.
    Schanz M, Braunschweig, Diebels S. A comparative study of Biot's theory and the linear theory of porous media for wave propagation problems[J]. Acta Mechanica,2003,161:13-235.
    Seed H B, Idriss I M. Soil moduli and damping factors for dynamic response analysis[M]. Report NoEERC 70-10, Earthquake Engineering Research Center, University of California Berkely,1970.
    Stoll R D, Bryan G M. Wave attenuation in saturated sediments[J]. The Journal of the Acoustical Society of America,1970,47:1440-1447.
    Stoll R D. Acoustic waves in ocean sediments[J]. Geophysics,1977,42:715-725.
    Stoll R D. Experimental studies of attenuation in sediments[J]. The Journal of the Acoustical Society of America,1979,66:1152-1160.
    Thomas M C, Wiltshire R J, Williams A T. The use of Fourier descriptors in the classification of particle shape[J]. Sedimentology,1995,42:635-645.
    Thornton C. Numerical simulations of discrete particle systems[J]. Powder Technology,2000,109 (Special Issue):292-301.
    Timoshenko S P, Goodier J N. Theory of elasticity[M]. Third edtion. Beijing: Tsinghua University Press,2004.
    Tsukada T, Anno Y. On the Approach between a sphere and a rough surface_1st. Report-analysis of contact radius and interface pressure[J]. Journal of the Japan Society for Precision Engineering,1979,45:473-479.
    Vardoulakis Ⅰ, Beskos D E. Dynamic behavior of nearly saturated porous media[J]. Mechanics of Materials,1986,5:87-108.
    Verruijt A. "Elastic storage of aquifers," In: de Weist RJM, editor. Flow through porous media[M]. London:Academic Press,1969:331-376.
    Walton K. The effective elastic moduli of a random packing of spheres [J]. Journal of the Mechanics and Physics of Solids,1987,35(2):213-226.
    Walton K. The oblique compression of two elastic spheres[J]. Journal of the Mechanics and Physics of Solids,1978,26:139-150.
    Wang S, Komvopoulous K. A fractal theory of the interfacial temperature distribution in the slow sliding regime:Part I-Elastic contact and heat transfer analysis[J]. Journal of Tribol,1994,116:812-823.
    Wang S, Komvopoulous K. A fractal theory of the interfacial temperature distribution in the slow sliding regime:Part II-Multiple domains, elastoplastic contacts and applications[J]. Journal of Tribol,1994,116:824-832.
    Yamamoto T, Turgut A. Acoustic wave propagation through porous media with arbitrary pore size distributions[J]. The Journal of the Acoustical Society of America,1988,83(5):1744-1751.
    Yang J, Sato T. On the velocity and damping of elastic waves in nearly saturated soils[C]. Proc.33rd Japan Nat. Conf. Geotech. Engng.,1998:1157-1158.
    Yang J, Sato T. Interpretation of seismic vertical amplification observed at an array site[J]. Bulletin of the Seismological Society of America,2000,90(2):275-285.
    Yang J, Sato T. Influence of water saturation on horizontal and vertical motion at a porous soil interface induced by incident P wave[J]. Soil Dynamics and Earthquake Engineering,2000,19:575-581.
    Yang J. A note on Rayleigh wave velocity in saturated soils with compressible constituents[J]. Canadian Geotechnical Journal,2001,38:1360-1365.
    Yang J, Sato T. Analytical study of saturation effects on seismic vertical amplification of a soil layer[J]. Geotechnique,2001,51 (2):161-165.
    Yang, J.. Saturation effects of soils on ground motion at free surface due to incident sv waves[J]. Journal of Engineering Mechanics,2002,128(3):1295-1303.
    Zhou Yan-guo, Chen Yun-min, Ding Hao-jiang. Analytical solutions to piezoelectric bimorphs based on improved FSDT beam model[J]. Smart Structures and Systems.2005, 1(3):309-324.
    Zhou Yan-guo, Chen Yun-min, Ding Hao-jiang. Analytical modeling of sandwich beam for piezoelectric bender elements[J]. Applied Mathematics and Mechanics (English Edition),2007,28(12):1581-1586.
    Bowen R M.混合物理论[M].南京:江苏科学技术出版社,1976.
    陈龙珠.饱和土中弹性波的传播速度及其应用[D].杭州:浙江大学,1987.
    陈云敏,陈颖平,黄博,姬美秀.在固结仪上安装压电陶瓷元土样波速测试装置,实用新型专利,专利号:ZL200520013094.2,授权公告日:2006年8月9日.
    陈云敏,周燕国,黄博.利用弯曲元测试砂土剪切模量的国际平行试验[J].岩土工程学报,2006,28(7):874-880.
    陈云敏,周燕国,黄博.弯曲元测试砂土剪切模量的国际平行试验[C].第24届土工测试学术研讨会论文集,黄河水利出版社,北京,2005:45-49.
    华南理工大学,东南大学,浙江大学,湖南大学.地基及基础[M].北京:中国建筑工业出版社,1998.
    胡泽荣,刘森英.颗粒的表面粗糙度[J].粉体技术,1998,4(3):1-3.
    姬美秀,陈云敏,黄博.弯曲元试验高精度测试土样剪切波速方法[J].岩土工程学报,2003,25(6):732-736.
    李保忠,蔡袁强.饱和度对横观各向同性准饱和多孔介质中弹性波传播的影响[J].水利学报,2003,9:94-101.
    李向维,李相约.饱水孔隙介质的质量耦合波动问题[J].应用数学与力学,1989, 10(4):309-314.
    刘建新,宋华,赵跃堂等.准饱和砂土中平面压缩波传播[J].防灾减灾工程学报,2004,24(1):86-92.
    刘旭.多相介质弹性参数的研究及波速计算[D].北京:中国地震局地球物理研究所,2002.
    门福录.波在饱含流体的孔隙介质中的传播问题[J].地球物理学报,1981,24(1):111-119.
    门福录地震波在含水层中的弥散和耗散[J].地球物理学报,1984,27(1):64-73.
    门福录,崔杰,袁晓铭等.含地下水的土层对地震波传播的影响[J].地球物理学报,1992,35(4):521-532.
    钱七虎,王明洋,赵跃堂三相饱和水土中爆炸波在障碍物上的反射荷载(I)[J].爆炸与冲击,1994,14(3):225-230.
    石兆吉.判别水平土层液化势的剪切波速法[J].水文地质工程地质,1986,4:9-13.
    孙其诚,王光谦.颗粒流动力学及其离散模型评述[J].力学进展,2008,1:87-100.
    汪闻韶.关于饱和砂土液化机理和判别方法的某些探讨[A].水利水电科学研究院论文集i第16集[C].北京:水利电力出版社,1984:1-8.
    魏龙,顾伯勤,冯飞,冯秀,孙见君.粗糙表面接触模型的研究进展[J].润滑与密封,34(7):112-117.
    吴世明.土动力学[M].北京:中国建筑工业出版社,2000.
    谢定义,齐吉琳,朱元林.土的结构性参数及其与变形-强度的关系[J].水力学报,1999,10:1-6.
    谢定义,齐吉琳.土的结构性及其定量化参数研究的新途径[J].岩土工程学报,1999,21(6):651-656.
    徐长节.非饱和土及准饱和土中波的传播[D].杭州:浙江大学,1997.
    张引科.非饱和土混合物理论及其应用[D].西安:西安建筑科技大学,2001.
    赵明阶,吕卫兵.多相土-石复合介质波动传播特性[J].岩石力学与工程学报,2005,24(supp.1):4917-4923.
    赵庆新,孙伟,郑克仁,姜国庆.水泥、磨细矿渣、粉煤灰颗粒弹性模量的比较[J].硅酸盐学报,2005,33:837-841.
    钟晓雄,袁建新.散粒体的微观组构与本构关系[J].岩土工程学报,1992,14(sup):39-48.
    周燕国.土结构性的剪切波速表征及对动力特性的影响[D].杭州:浙江大学,2007.
    周新民.准饱和土波动特性及动力响应研究[D].杭州:浙江大学,2006.

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