用户名: 密码: 验证码:
随机场理论在地基可靠度分析中的应用研究
详细信息    本馆镜像全文|  推荐本文 |  |   获取CNKI官网全文
摘要
工程设计是在存在大量不确定性和某些未知因素的情况下进行的。对于这种不确定性,较之传统采用的定值设计法,可靠度的设计方法更为先进和科学。然而,由于岩土工程的特殊性和复杂性,目前国内外对于地基可靠度的研究与应用远落后于结构工程。其主要原因是算得的可靠度指标过小,对应的失效概率太大,常常超过10%,即使对已证明是安全稳定的工程也是如此。造成这种理论与实际情况背离的主要原因,是由于现在常用的数理统计方法忽略了岩土材料具有自相关性的特点,导致其方差估算偏大。本文针对这一问题,将随机场理论引入岩土工程的地基可靠度分析之中,研究土的相关性在概率分析中对土性的影响。
     本文首先根据随机场理论,结合天津港地区的大量现场勘察资料,建立起天津港地基土性剖面的随机场模型,并对其土性剖面的平稳性和各态历经性进行了检验;对现有的求解相关距离的递推空间法和相关函数法进行比较和研究,从理论上证明当样本容量足够大时,两种方法的计算结果可以得到统一;并分别对其作出改进,提出波动函数法、加权拟合相关函数法和拟合折减函数法,使相关距离的计算更加简便易行且精度有所提高。
     应用改进的相关函数拟合方法和相关距离计算方法,通过大量计算分析和数值模拟,证明天津港典型土层垂直方向和水平方向的土性剖面随机场的相关函数都为指数余弦型,并通过统计分析得出天津港地区典型土层相关距离的范围值。将随机场理论引入抗剪强度指标的统计方法,提出了按随机场统计的传统法、简化相关法、正交变换法,可分别从不同角度对土性指标的自相关性和互相关性加以考虑。
     提出了随机场的另一种特征尺度——“完全不相关距离”的概念;探讨了在土工可靠度计算中如何正确选取并合理应用方差折减函数;并根据相关距离、完全不相关距离、有效影响深度的关系,提出了方差折减函数的确定原则;根据分析统计的天津港地区典型土层的相关特性,确定了本地区标准差折减的范围值。
     将研究得到的相关函数和方差折减函数,应用到港口边坡稳定可靠度分析中,重新验算和校核现有工程的安全性指标,分析结果表明随机场理论的应用对地基可靠度起到了重要作用,按照方差折减函数的确定原则对强度指标进行方差折减后得到的可靠度指标与工程的实际安全程度较为匹配,可为港口工程地基可靠度规范的修订提供一定的理论依据。
The engineering design is usually undertaken with a great deal of uncertainties and unknown factors. Therefore, the reliability theory based design method is more advanced and reasonable compared with the traditional determination design method. However, the research and application of using reliability theory in soil foundation design is much more complicated and far behind that in structure engineering at present. The dominant problem is that when designing a soil foundation with the reliability procedure, the calculated reliability index is often too small to be accepted, which gives the corresponding failure probability greater than 10%, even for the foundations that have been proved in safe conditions. The main reason why the theory deviates from actual conditions is that the auto-correlation of soil properties is ignored when using the common statistic method, which results in the over estimated variance of the parameters used for design. In this dissertation, the random field theory is applied to the reliability analysis of foundations in geotechnical engineering and the effect of correlation of soil on probability analysis is studied.
     According to the random field theory, some theoretical models are established for the soil profiles in Tianjin Harbor based on a large amount of investigation data, including the unit weight, water content, compressibility index and mechanical indexes, such as cohesion and inner frictional angle of foundation soils. Then the stationarity and ergodicity of soil profiles are examed, which should be the basic principle of the random theory. The conception of correlation distance is discussed and two traditional different methods for estimating the correlation distance are compared and studied. It is proved that the results obtained by both methods are approximately the same if the number of samples is large enough. In addition, both methods are improved respectively in order to make the calculation easier and get a more precise result.
     It is proved that the correlation functions of the random field models for the vertical and horizontal soil profiles in Tianjin Harbor can be expressed with exponential-cosine type and the representative values of correlation distance of local area are provided based on a great deal of calculation and curve fitting.
     The random field theory is also introduced into the statistical methods for characteristics of shear strength. The improved traditional method, the simplified correlation method and the cross transform method are presented in order that both of the auto-correlation and cross-correlation of the shear strength of soils can be considered in reliability analysis.
     The irrelated distance is presented as another characteristic parameter for the random field. How to correctly choose the reduction function of variance and how to reasonably apply it to the reliability analysis are discussed in very detail. Thereafter, the principle for determinating the reduction function of variance is presented according to the relationship of correlation distance, irrelated distance and effective depth in soil mechanics. The representative reduction function of variance of local area is put forward based on the statistic analysis on correlation characteristic of typical soil stratum in Tianjin Harbor.
     The correlation function and reduction function of variance are applied to the probabilistic slope stability analysis and the reliabilities of some practical projects are recalculated. It is proved that the reliability indexes obtained by reducing the variance of shear strength indexes according to the method developed in this thesis agree well with the reliability of practical engineering. The developed method may give guidance to apply the theory of random field to the reliability analysis of soil foundations.
引文
[1]高大钊.岩土工程设计中安全度指标及其应用[J].工程勘察,1998,1:1-6.
    [2]包乘纲,高大钊,张庆华.地基工程可靠度分析方法研究[M].武汉:武汉测绘科技大学出版社,1996.
    [3] Vanmarcke Erik H. Probabilistic Modeling of Soil Profiles[J]. Journal of the Geotechnical Engineering Division,ASCE,1977,103(GT11):1227 -1246.
    [4]彭大鹏.齐次随机场在分析土性指标中的应用[J].天津大学学报,1992,2:118-124.
    [5]高大钊.土力学可靠性原理[M].北京:中国建筑工业出版社,1989.
    [6]闫澍旺,贾小黎,郭怀志.土性剖面随机场模型的平稳性和各态历经性验证[J].岩土工程学报,1995,17(3):1-9.
    [7]刘春原,闫澍旺.岩土参数随机场特性及线性预测[J].岩土工程学报,2002,24(5): 588-591.
    [8]李镜培,舒翔,丁士君.土性指标的自相关特征参数及其确定原则[J].同济大学学报,2003,31(3):287-290.
    [9]徐斌,王大通,高大钊.用相关函数法求静探曲线相关距离的讨论[J].岩土力学,1998,19(1):55-58.
    [10]朱登峰,高大钊.土性平稳随机场的空间统计特性分析[J].岩土力学,2003, 24(3):455-462.
    [11]刘润,闫澍旺,周宏杰,等.空间随机场模型的建立与桩基竖向承载力的可靠度分析[J].岩土力学,2004,25(10):1603-1608.
    [12]包承纲,黄卫峰,张庆华.随机场理论在重力式码头地基承载力计算中的应用.见:地基工程可靠度分析方法研究[M].武汉:武汉测绘科技大学出版社,1996:110-117.
    [13]熊启东,高大钊.上海地区地基承载力的可靠度分析[J].岩土力学,1997, 18(1):73-77.
    [14]高大钊.土的抗剪强度指标的统计与应用.见:地基工程可靠度分析方法研究[M].武汉:武汉测绘科技大学出版社,1996:98-104.
    [15]孙万禾,黄传志,叶国良等.土的抗剪强度指标统计方法的分析[J].港口工程, 1996,(3):5-16.
    [16]港口工程地基规范(JTJ250-98),1998,4.
    [17]张庆华,包承纲.改进JC法及其在土工可靠度计算中的应用.见:地基工程可靠度分析方法研究[M].武汉:武汉测绘科技大学出版社,1996:105-109.
    [18]文圣常,余宙文.海浪理论与计算原理[M].北京:科学出版社,1984.
    [19]松尾埝著,万国朝,李杨海译.地基工程学[M].北京:人民交通出版社,1990.
    [20]孙万禾,黄传志,陈环.边坡稳定可靠度的分析[J].港口工程,1991,(2):36-41.
    [21]黄传志.土的抗剪强度统计方法探讨[J].水运工程,1989,(1): 47-53.
    [22]黄传志.土性概率参数分析中的几个问题[J].水运工程,1994,(4) :5-16.
    [23]贾晓黎.土性剖面的随机场特性及其应用研究[D].天津大学硕士论文,1985.
    [24]刘润.海工结构物地基可靠度及随机有限元分析[D].天津大学博士论文,2001.
    [25]刘润,闫澍旺.渤海湾地基土随机场特性及可靠度分析[J].岩土工程学报. 2004,26(4) :464-467.
    [26]闫澍旺,周宏杰,刘润.海工结构物桩基础竖向稳定性的可靠度分析[J].海洋工程. 2004,22(1) :19-24.
    [27]刘润,闫澍旺.信息管理技术在海洋工程地基可靠度分析中的应用[J].海洋技术.2004, 23(4):90-95.
    [28]刘润,闫澍旺.软粘土边坡稳定性分析中十字板强度取值的探讨[J].岩石力学与工程学报,2005,24(8).
    [29]黄广龙,龚晓南,肖溟.土性参数的随机场模型及桩体沉降变异特性分析[J].岩土力学,2000,21(4):311-315.
    [30]陈晓平,孙慕群,吴起星.软基上复杂土坡稳定可靠度研究[J].岩石力学与工程学报,2004,23(6):925-929.
    [31]杨强,陈新,周维垣.抗剪强度指标可靠度分析[J].岩石力学与工程学报,2002, 21(6):868-873.
    [32]梧松,吴玉山.边坡可靠度的随机斜条分法上限解[J].岩石力学与工程学报, 2003,22(10):1727-1729.
    [33]胡小荣,唐春安.岩土力学参数随机场的空间变异性分析及单元体力学参数赋值研究[J].岩石力学与工程学报, 2000,19(1):59-63.
    [34]胡小荣,唐春安.岩土力学参数随机场的离散研究[J].岩土工程学报, 1999, 21(4):450-455.
    [35]郭怀志,彭大鹏.材料性能的随机场特性参数的检定方法[J].岩土工程学报, 1994,16(3) :79-83.
    [36]李镜培,高大钊.桩基承载力参数估计的随机场模型[J].岩土工程师,1992, 4(2) :1-6.
    [37]张征,程祖峰.岩土参数随机场空间最优估计精度分析与特异值研究[J].岩土工程学报, 1999,21(5) :586-590.
    [38]冷伍明,赵善锐.土工参数不确定性的计算分析[J].岩土工程学报, 1995, 17(2) :68-74.
    [39]李启信,White.W.土层的概率模型及其在桩基分析中的应用[J].岩土工程学报, 1989,11(6) :120-128.
    [40]陈木法.随机场概论[J].数学进展, 1989,18(3) :294-322.
    [41]庞小朝,周小文.随机场的模拟及其在堤坡可靠度分析中的应用[J].长江科学院院报, 2002,19(4) :27-29,48.
    [42]马克生,杨晓军.空间随机土作用下的柔性桩沉降可靠度分析[J].浙江大学学报,2000,34(4):366-369.
    [43]周小文,付晖,吴昌瑜.地层特性随机场插值特性研究[J].岩土力学,2005, 26(2):221-224.
    [44]傅旭东.静力触探参数相关范围的估算[J].岩土力学,1999,20(4):76-80.
    [45]谢康和,虞颜.粘性土地基固结的空间概率特性[J].浙江大学学报,2002, 36(5):588-590.
    [46]茜平一,陈晓平.天然地基承载力可靠度的研究[J].岩土力学,1999, 20(2):41-45.
    [47]李小勇,谢康和.土性参数相关距离的计算研究和统计分析[J].岩土力学, 2000,21(4):350-353.
    [48]白顺果,张鸿儒,黄春霞.考虑土性参数空间变异性的地基承载力可靠度分析[J].北方交通大学学报,2004,28(1):32-34,73.
    [49]余跃心,刘汉龙,高玉峰.计算相关距离的神经网络法[J].岩土力学,2003, 24(5):719-722.
    [50]洪昌华,龚晓南.土性空间变异性的统计模拟[J].浙江大学学报,2000, 34(5):527-530.
    [51]张维秀,盛崇文.地基土抗剪强度指标统计的方差分离法[J].岩土工程学报. 1992,14(2) :55-60.
    [52]李小勇,谢康和.土工测试数据的可靠性检验[J].岩土工程师.2000, 12(1) :11-14.
    [53]赵国藩,曹居易,张宽权.工程结构可靠度[M].北京:水利电力出版社,1984.
    [54]吴世伟.结构可靠度分析[M].北京:人民交通出版社,1990.
    [55]桑国光,张圣坤.结构可靠性原理及其应用[M].上海:上海交通大学出版社,1986.
    [56]钱家欢,殷宗泽.土工原理与计算[M].北京:水利电力出版社,1994.
    [57]黄文熙.土的工程性质[M].北京:水利电力出版社,1983.
    [58]魏汝龙.软粘土的强度和变形[M].北京:人民交通出版社,1987.
    [59] H.F.温特科恩,方晓阳著,钱鸿缙,叶书麟译.基础工程手册[M].北京:中国建筑工业出版社,1994.
    [60]朱百里,沈珠江.计算土力学[M].上海:上海科学技术出版社,1990.
    [61]钱家欢,殷宗泽.土工数值分析[M].北京中国铁道出版社,1991.
    [62]张学言.岩土塑性力学[M].北京:人民交通出版社,1993.
    [63]龚晓南.土塑性力学[M].杭州:浙江大学出版社,1990.
    [64]天津大学等编著.土力学与地基[M].北京:人民交通出版社,1986.
    [65]陈仲颐,叶书麟.基础工程学[M].北京:中国建筑工业出版社,1990.
    [66]郑大同.地基极限承载力的计算[M].北京:中国建筑工业出版社,1979.
    [67] C.Preston著,严士健等译.随机场[M].北京:北京师范大学出版社,1982.
    [68]罗定安.工程结构数值分析方法与程序设计[M].天津:天津大学出版社,1995.
    [69] Steven Holzner著,详实翻译组译.Visual Basic6技术内幕[M].北京:机械工业出版社,1999.
    [70] Noel Jerke著,京京翻译组译.Visual Basic6开发人员指南[M].北京:机械工业出版社,1998.
    [71]侯钊等编著.天津软土地基[M].天津:天津科学技术出版社,1987.
    [72] Yan Shuwang,Zhou Hongjie,Liu Run. Reliability analysis on axially loaded pile foundation of offshore platforms[J]. Frontiers in Offshore Geotechnices,Perth, Australia,2005,9: 853-858.
    [73] Vanmarcke Erik H. Reliability of earth slopes[J]. Journal of the Geotechnical Engineering Division, ASCE,1977,103(GT11):1246-1265.
    [74] K.S.Li, P.Lumb. Probabilistic design of slopes[J]. Journal of the Can. Geotech, 1987,24:520-535.
    [75] John T.Christian, Charles C.Ladd, Gregory B.Baecher. Reliability applied to slope stability analysis[J]. Journal of the Geotechnical Engineering, ASCE,1994,120(12):2180-2207.
    [76] Gordon A.Fenton, D.V.Griffiths.Bearing-capacity prediction of spatially random c-φsoils[J]. Journal of the Can. Geotech, 2003,40:54-65.
    [77] C.Cherubini. Reliability evaluation of shallow foundation bearing capacity on c’,φ’soils[J]. Journal of the Can. Geotech, 2000,37:264-269.
    [78] Don J DeGroot, Gregory B.Baecher. Estimating autocovariance of in-situ soil properties[J]. Journal of the Geotechnical Engineering, ASCE,1993, 119(1):147-165.
    [79] D.W.Meek. A semiparametric method for estimating the scale offluctuation[J]. Compuer & Geosciences, 2001,27:1243-1249.
    [80] Francesco Cafaro, Claudio Cherubini. Large sample spacing in evaluation of vertical strength variability of clayey soil[J]. Journal of the Geotechnical and Geoenvironmental Engineering, ASCE,2002,128(7):558-568.
    [81] Mark B.Jaksa, Peter I.Brooker, William S.Kaggwa.Inaccuracies associated with estimating random measurement errors[J]. Journal of the Geotechnical and Geoenvironmental Engineering, ASCE,1997,123(5):393-401.
    [82] Kok-Kwang Phoon, Ser-Tong Quek, Ping An.Identification of statistically homogeneous soil layers using modified Bartlett statistics[J]. Journal of the Geotechnical and Geoenvironmental Engineering, ASCE,2003,129(7):649 -659.
    [83] Gordon A.Fenton. Random field modeling of CPT data[J]. Journal of the Geotechnical and Geoenvironmental Engineering, ASCE,1999,125(6):486 -498.
    [84] Gordon A.Fenton. Estimation for stochastic soil models[J]. Journal of the Geotechnical and Geoenvironmental Engineering, ASCE,1999,125(6):470 -485.
    [85] V.Ravi. Statistical modelling of spatial variability of undrained strength[J]. Journal of the Can. Geotech, 1992,29:721-729.
    [86] Jaroslaw Przewlócki. Two-dimensional random field of mechanical soil properties[J]. Journal of the Geotechnical and Geoenvironmental Engineering, ASCE,2000,126(4):373-377.
    [87] M.Soulié, P.Montes, V.Silvestri. Modelling spatial variability of soil paramters[J]. Journal of the Can. Geotech, 1990,27:617-630.
    [88] Winterkom H. F., Fang H. Y. Foundation engineering Handbook[M],1975.
    [89] Gordon A.Fenton, D.V.Griffiths. Three-dimensional probabilistic foundation settlement[J]. Journal of the Geotechnical and Geoenvironmental Engineering, ASCE, 2005, 131(2): 232-239.
    [90] Gordon A.Fenton, D.V.Griffiths. Probabilistic foundation settlement on spatially random soil[J]. Journal of the Geotechnical and Geoenvironmental Engineering, ASCE, 2002, 128(5):381-390.
    [91] J. Michael Duncan. Factors of safety and reliability in geotechnical engineering[J]. Journal of the Geotechnical and Geoenvironmental Engineering, ASCE, 2000, 126(4):307-316.
    [92] D.V.Griffiths, Gordon A.Fenton, N. Manoharan. Bearing capacity of rough rigid strip footing on cohesive soil: Probabilistic study [J]. Journal of the Geotechnical and Geoenvironmental Engineering, ASCE, 2002, 128(9):743-755.
    [93] G.M.Paice, D.V.Griffiths, Gordon A.Fenton. Finite element modeling of settlements on spatially random soil [J].Journal of the Geotechnical Engineering, ASCE, 1996, 122(9):777-779.
    [94] D.V.Griffiths, Gordon A.Fenton. Probabilistic slope stability analysis by finite elements[J]. Journal of the Geotechnical and Geoenvironmental Engineering, ASCE, 2004, 130(5):507-518.
    [95] Azm S. Al-Homoud, Najat Tanash. Modeling uncertainty in stability analysis for design of embankment dams on difficult foundations[J]. Engineering Geology,2004,71:323-342.
    [96] A.S. Al-Homoud, W.W. Tahtamoni. Reliability analysis of three-dimensional dynamic slope stability and earthquake-induced permanent displacement[J]. Soil dynamics and earthquake engineering,2004,19:91-114.
    [97] Ahmed M. Hassan, Thomas F. Wolff. Search algorithm for minimum reliability index of earth slopes[J].Journal of the Geotechnical and Geoenvironmental Engineering, ASCE, 1999, 125(4):301-308.
    [98] D.V.Griffiths, Gordon A.Fenton.Three-dimensional seepage through spatially random soil[J].Journal of the Geotechnical and Geoenvironmental Engineering, ASCE, 1997, 123(2):153-160.
    [99] Peter Hall, Prakash Patil. Properties of nonparametric estimators of autocovariance for stationary random fields[J].Probability Theory and Related Field,1994,99(3):399-424.
    [100] R. Baker. Modeling soil variability as a random field [J]. Mathematical Geology, 1984,16(5): 435-448.
    [101] P. Goovaerts. Geostatistical modelling of uncertainty in soil science[J]. Geoderma, 2001, 103(1):3-26.
    [102] G. Philip Robertson, James R. Crum,Boyd G. Ellis. The spatial variability of soil resources following long-term disturbance[J]. Oecologia,1993,96(4):451-456.
    [103] Chien Yi-Ju, Lee Dar-Yuan, Guo Horng-Yuh,Houng Kun-Huang. Geostatistical analysis of soil properties of mid-west taiwan soils[J]. Soil Science,1997,162(4):291-298.
    [104] G. B. M. Heuvelink, R. Webster. Modelling soil variation: past, present, and future[J]. Geoderma, 2001, 100(3):269-301.
    [105] J. Przewócki, J. Górski. Strip foundation on 2-D and 3-D random subsoil[J]. Probabilistic Engineering Mechanics ,2001,16(2):121-136.
    [106] M. Uzielli, G. Vannucchi, K. K. Phoon. Random field characterisation of stress-normalised cone penetration testing parameters[J].Geotechnique,2005, 55(1):3-20.
    [107] Kok-Kwang Phoon, Ser-Tong Quek, and Ping An. Geostatistical analysis of cone penetration test (CPT) sounding using the modified Bartlett test[J]. Journal of the Can. Geotech ,2004, 41: 356-365.
    [108] Vrouwenvelder Ton, Calle Ed. Measuring Spatial Correlation of Soil Properties[J]. Heron. 2003, 48( 4):297-311.
    [109] Dieter Stolle, Peijun Guo, Gabriel Sedran. Impact of random soil properties on stress–strain response[J]. Journal of the Can. Geotech ,2004, 41: 351-355.
    [110] R. M. Lark. Optimized spatial sampling of soil for estimation of the variogram by maximum likelihood[J]. Geoderma, 2002, 105(1):49-80.
    [111] Chowdhury R N,Tang W H, Sidi I. Reliability model of progressive slope failure[J]. Geotechnique, 1987,37( 4):467-481.
    [112] H. El-Ramly, N.R. Morgenstern, D.M. Cruden. Probabilistic slope stability analysis for practice[J]. Journal of the Can. Geotech ,2002, 39: 665–683.
    [113] Whitman V. W. Evaluating calculated risk in geotechnical engineering[J]. Journal of Geotechnical Engineering, ASCE, 1984(110):145–188.
    [114] Tang, W. H., Yucemen, M. S., Ang, A.H.S. Probability based short-term design of slopes[J]. Canadian Geotechnical Journal, 1976(13): 201–215.
    [115] Nguyen, V. U., Chowdhury, R. N. Simulation for risk analysis with correlated variables[J]. Géotechnique, 1985(35): 47–58.
    [116] Matsuo, M., and Kuroda, K. Probabilistic approach to design of embankments[J]. Soils and Foundations, 1974(14): 1–17.
    [117] Lumb, P.The variability of natural soils[J]. Canadian Geotechnical Journal, 1966(3): 74–97.
    [118] Li, K.S. Discussion: probabilistic potentiometric surface mapping[J].Journal of Geotechnical Engineering, ASCE, 1991(117): 1457–1458.
    [119] Honjo, Y., and Kuroda, K. A new look at fluctuating geotechnical data for reliability design[J]. Soils and Foundations, 1991(31):110–120.
    [120] Alonso, E.E.Risk analysis of slopes and its application to slopes in Canadian sensitive clays[J].éotechnique, 1976(26): 453–472.
    [121] Heuvelink Pebesma, G.B.M. Heuvelink, E.J. Pebesma. Spatial aggregation and soil processes modelling[J]. Geoderma, 1999 (89):47–65.

© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号

地址:北京市海淀区学院路29号 邮编:100083

电话:办公室:(+86 10)66554848;文献借阅、咨询服务、科技查新:66554700