降雨影响下黄土边坡稳定性的分析
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摘要
边坡是自然界的地质体,是人类生产生活的最普遍的地理环境,与人们的各种活动密切相关,它的稳定性受多种因素的影响制约,譬如地层特性、地形地貌、地质构造、地下水、地震作用、人为活动等。因此,边坡的稳定性表现出动态的、非确定性的基本特性,其稳定性分析一直是岩土工程领域重要的研究课题,在工程实践中占据相当重要的地位。
黄土地区边坡问题尤为突出,该地区由于受干旱半干旱气候的影响,黄土边坡基本属于非饱和土质边坡。基质吸力在控制非饱和土体力学性质方面起着十分重要的作用,在降雨入渗情况下,雨水的入渗使得边坡顶部非饱和区缩小,出现局部暂态饱和区,导致边坡土体基质吸力下降,抗剪强度减小,从而导致边坡稳定性的下降,因此,降雨入渗是导致边坡失稳的主要因素,是本文的研究重点。
由于边坡稳定性分析方法很多,不同的方法又各具特点,有一定的适用条件。如何根据具体的边坡工程地质条件,具体的分析目的与精度要求,合理有效地选用与之相适应的边坡稳定性分析方法,是一项很重要的工作。目前边坡稳定性分析方法主要分为两大类：确定性分析方法和不确定性分析方法。
本文主要考虑降雨入渗影响下的非饱和黄土边坡稳定性分析方法,运用非饱和土水分子运动方程,求解降雨入渗条件下边坡土体的吸水率,又考虑到其与非饱和土抗剪强度的关系,首先利用确定性分析方法中最具代表性的极限平衡法对非饱和黄土边坡稳定性进行了评价；由于边坡工程是一个复杂的开放系统,影响因素较多,并且带有相当的随机性、模糊性和不确定性,沿用传统的力学方法进行计算分析,存在许多问题和不足,因此,本文还针对相同条件下的黄土边坡稳定性用人工神经网络方法进行评价,并对两种方法的评价结果进行比较分析。
Slope, the geological body of the nature,is the most common geographical environment of human production and life, and closely related to the various activities of human beings. Because its stability is affected by many factors constraining, such as strata characteristics, topography, geological structure, groundwater, earthquake, human activities,etc.,the performance of slope stability turns out dynamic, non-deterministic.So its stability analysis of geotechnical engineering has been an important research topic, occupying an important position in engineering practice.
Loess slope is particularly prominent in the region. Due to the arid and semi-arid climate, loess slope essentially is classified into unsaturated soil slope.With regard to controlling physical properties of unsaturated soil, matricsuction plays an important role.In the case of rainfall infiltration,water infiltration so narrows unsaturated zone at the top of slope, and local temporary saturated zone presents, leading to decreased matricsuction of slope soil body, and weak shear strength, thus a decline in slope stability. It can be concluded that rainfall infiltration is the main factor contributing to slope instability, which is the focus of this study.
There are many different ways to analyze the slope stability, and their characteristics differ under certain conditions of application. So it is believed to be exceptionally important to adopt reasonable and effective methods suitable to give one appropriate analysis on slop stability according to engineering geological conditions, the specific purpose of analysis and accuracy. Slope-stability-analysis methods currently fell into two categories:certain analysis and uncertain analysis.
This paper is to employ slope stability analysis on unsaturated soil under the influence of rainfall infiltration, introducing motion equation of water molecular from unsaturated soil for the solution to moisture content in slope soil under the rainfall infiltration, but also taking into account the relationship between it and shear strength of non-saturated soil.So this paper firstly adopted the limit equilibrium method, the most typical one of the certainty analysis to value non-saturated loess slope stability;Since engineering is a complex open system, influenced by many factors and with considerable random, fuzzy and uncertainty, the traditional mechanical method of calculation had many problems and shortcomings,therefore, this article is devoted to providing an evaluation on loess slope stability with artificial neural network in response to the same conditions,and evaluation results of the two methods were compared.
黄土地区边坡问题尤为突出,该地区由于受干旱半干旱气候的影响,黄土边坡基本属于非饱和土质边坡。基质吸力在控制非饱和土体力学性质方面起着十分重要的作用,在降雨入渗情况下,雨水的入渗使得边坡顶部非饱和区缩小,出现局部暂态饱和区,导致边坡土体基质吸力下降,抗剪强度减小,从而导致边坡稳定性的下降,因此,降雨入渗是导致边坡失稳的主要因素,是本文的研究重点。
由于边坡稳定性分析方法很多,不同的方法又各具特点,有一定的适用条件。如何根据具体的边坡工程地质条件,具体的分析目的与精度要求,合理有效地选用与之相适应的边坡稳定性分析方法,是一项很重要的工作。目前边坡稳定性分析方法主要分为两大类：确定性分析方法和不确定性分析方法。
本文主要考虑降雨入渗影响下的非饱和黄土边坡稳定性分析方法,运用非饱和土水分子运动方程,求解降雨入渗条件下边坡土体的吸水率,又考虑到其与非饱和土抗剪强度的关系,首先利用确定性分析方法中最具代表性的极限平衡法对非饱和黄土边坡稳定性进行了评价；由于边坡工程是一个复杂的开放系统,影响因素较多,并且带有相当的随机性、模糊性和不确定性,沿用传统的力学方法进行计算分析,存在许多问题和不足,因此,本文还针对相同条件下的黄土边坡稳定性用人工神经网络方法进行评价,并对两种方法的评价结果进行比较分析。
Slope, the geological body of the nature,is the most common geographical environment of human production and life, and closely related to the various activities of human beings. Because its stability is affected by many factors constraining, such as strata characteristics, topography, geological structure, groundwater, earthquake, human activities,etc.,the performance of slope stability turns out dynamic, non-deterministic.So its stability analysis of geotechnical engineering has been an important research topic, occupying an important position in engineering practice.
Loess slope is particularly prominent in the region. Due to the arid and semi-arid climate, loess slope essentially is classified into unsaturated soil slope.With regard to controlling physical properties of unsaturated soil, matricsuction plays an important role.In the case of rainfall infiltration,water infiltration so narrows unsaturated zone at the top of slope, and local temporary saturated zone presents, leading to decreased matricsuction of slope soil body, and weak shear strength, thus a decline in slope stability. It can be concluded that rainfall infiltration is the main factor contributing to slope instability, which is the focus of this study.
There are many different ways to analyze the slope stability, and their characteristics differ under certain conditions of application. So it is believed to be exceptionally important to adopt reasonable and effective methods suitable to give one appropriate analysis on slop stability according to engineering geological conditions, the specific purpose of analysis and accuracy. Slope-stability-analysis methods currently fell into two categories:certain analysis and uncertain analysis.
This paper is to employ slope stability analysis on unsaturated soil under the influence of rainfall infiltration, introducing motion equation of water molecular from unsaturated soil for the solution to moisture content in slope soil under the rainfall infiltration, but also taking into account the relationship between it and shear strength of non-saturated soil.So this paper firstly adopted the limit equilibrium method, the most typical one of the certainty analysis to value non-saturated loess slope stability;Since engineering is a complex open system, influenced by many factors and with considerable random, fuzzy and uncertainty, the traditional mechanical method of calculation had many problems and shortcomings,therefore, this article is devoted to providing an evaluation on loess slope stability with artificial neural network in response to the same conditions,and evaluation results of the two methods were compared.
引文
[1]陈立宏,陈祖煜.岩土工程中的安全系数和可靠度[J].水利规划设计.2002,(2)：57-62.
[2]郑颖人,赵尚毅.边坡工程设计中安全系数的讨论[J].岩石力学与工程学报.2006,25(9)：1938-1940.
[3]陕西省宝鸡峡工程指挥部,陕西省宝鸡峡引渭灌溉管理局,陕西省水利电力勘测设计院.宝鸡峡引渭灌溉工程技术总结[M].13-16.
[4]王家臣,洛中洲.关于边坡稳定可靠性分析的几点看法[J].世界煤炭技术.1999,(7)：16-20.
[5]龚宪伟,易念平,张信贵.对边坡工程安全系数的思考[J].广西大学学报.2006,31(3)：265-270.
[6]陈祖煜.土质边坡稳定分析—原理,方法,程序[M].中国水利水电出版社,2003土工程学报.2007,29(1)：147-151.
[7]饶文英,郭增玉.黄土高边坡的滑坡机理与稳定分析方法探讨[J].陕西机械学院学报.1988,4(2)：47-62.
[8]Hovland H. J. Three-dimensional slope stability analysis method[J].Journal of the Geotechnical Engineering, Division Proceed2ings of the American Society of Civil Engineers,1977,103(GT9):971-986.
[9]陈祖煜,张广文.关于“土坡稳定性分析”一文的讨论[J].岩土工程学报,1995,17(6)
[10]刘三仓,隋国秀,刘志伟.非饱和-饱和状态下黄土地基中灌注桩承载性能的研究[J].岩土工程学报.2007,29(1)：147-151.
[11]HungrO,Salgado F.M. Byrne P.M. Evaluation of a three-di2mensional method of slope stability analysis[J].CanadianGeotechnical Journal,1989,(26): 679-686.
[12]HungrO.An extension of Bishop's simp lified method of slope stability analysis to threedimensions[J].Geotechnique,1987,37(1):113-117.
[13]李文广.考虑降雨入渗影响的非饱和土边坡突变失稳的研究[D].西安建筑科技大学硕士学位论文,2004.
[14]卢肇钧等.膨胀力在非饱和土强度理论中的应用[J].岩土工程学报,1997(5)：20-27.
[15]钱家欢,殷宗泽.土工原理与计算[M].中国水利水电出版社(第二版),1997.
[16]王晓峰.降雨入渗对非饱和土边坡稳定性影响的分析[D].西安建筑科技大学硕士论文,2003.
[17]党进谦,郝月清.吸水率对黄土结构强度的影响[D].西北水资源与水工程,1998(2)：15-19.
[18]唐晓松,郑颖人.水位下降过程中超孔隙水压力对边坡稳定性的影响[J].水利水运工程学报,2007(1)：1-6.
[19]D.G弗雷德朗德,H.拉哈尔佐.非饱和土力学[M],中国建筑工业出版社,1997.8.
[20]赵慧丽,马易鲁,非饱和土抗剪强度研究方法的探讨[J]岩土工程技术,2001.3.
[21]Fei Cai,Keioz Ugai.Numerical analysis of the stability of a slope reinforced with piles[J].Soil and Foundations,2000,40(1):73-84.
[22]孙敏.饱和-非饱和渗流影响因素及对土坡稳定性影响研究[D].南京：河海大学.
[23]ZhangX.Three-dimensional stability analysis of concave slopes In plan view[J].Jouornal of Geotechnical Engineering,ASCE,1988,(114):658-671.
[24]陈祖煜,弥宏亮,汪小刚.边坡稳定三维分析的极限平衡方法[J].岩土工程学报.2001,23(5)：524-529.
[25]H. F. Schweiger, G. M. Peschl."Reliability analysis in geotechnics with the random setfinite element method"[J].Computer and Geotechnics.32(2005) 422-435.
[26]Fellenius W Calculation of the stability of earth slope[J].Transactions of 2nd Congress on Large Dams,Washington, D C,1936:445-462.
[27]徐捷,王钊,李未显.非饱和土吸力量测技术[J].岩石力学与工程学报,2000.6.
[28]肖桃李,李新平,米健.土质边坡稳定性影响因素的研究[J].地质灾害与环境保护.
[29]Bishop A W. The use of slip circle in the stability analysis of slopes[J]. Geotechnique,1955,1(1):7-17.
[30]Janbu N. Application of composite slip surface for stability analysis[A]. Proc.,European Conf.on stability of earth slopes[C],Sweden,1954(3), 43-49.
[31]Sanna S K. Stability analysis of embankments and slopes[J].Geotechnical, 1973,23(3):423-33.
[32]Morgenstern N R, Price V E.The analysis of the stability of general slip Surfaces[J]. Geotechnique,1965,15(1),79-3.
[33]Spencer E.A method of analysis of the stability of embankments assuming parallel inter-slice forces[J].Geotechnique,1967,17(1):11-6.
[34]Janbu N. Slope stability computations[A].In:Hirschfield E, Poulos S,Editors, Embankment Dam Engineering[C].New York:John Wiley,1973:47-6.
[35]Chen Zhuyu, Morgenstern N R. Extensions to the generalized method of slices for stability analysis[J].Canadian Geotechnical Journal 1983,20(1): 104-19.
[36]郑颖人,赵尚毅,时卫民,林丽.边坡稳定分析的一些进展[J].地下空间,2001,21(4)：262-271.
[37]Duncan J M. State of the art:limit equilibrium and finite-element Analysis of slope[J].Journal of Geotechnical and Geoenvironmental Engineering, ASCE,1996,122(7):577-596.
[38]陈祖煜.土坡稳定分析原理方法程序[M].中国水利水电出版社,2003239-248.(Chen Zhuyu.Soil slope stability analysis-Theory Method and Programs[M].China Water Power Press,2003,239-248.(in Chinese)). 1988,4(2):47-62.
[39]卢肇钧等.非饱和土的抗剪强度与膨胀压力[J].岩土工程学报,1992(3)：1-8.
[40]党进谦,李靖.非饱和黄土的强度特征[J].岩土工程学报,1997(2)：56-61.
[41]汤连生.从粒间吸力特性再认识非饱和土抗剪强度理论阴.岩土工程学报,2001.
[42]毛昶熙主编.渗流计算分析与控制[M].中国水利水电出版社,2003.2007,18(2)：89-93.
[43]孙敏.饱和-非饱和渗流影响因素及对土坡稳定性影响研究[D].南京：河海大学,2005：32-38.
[44]贺可强.雷建和边坡稳定性的神经网络预测研究[期刊论文]-地质与勘探2001(6).
[45]陈昌彦.王思敬.沈小克边坡岩体稳定性的人工神经网络预测模型[期刊论文]-岩土工程学报2001(2).
[46]夏元友.李新平.程康用人工神经网络估算岩质边坡安全系数工程1998(02).
[47]弥宏亮.陈祖煜遗传算法在确定边坡稳定最小安全系数中的应用[期刊论文]-岩土工程学报2003(6).
[48]包惠明.胡长顺基于ANN下的岩质路堑深边坡稳定性评价[期刊论文]-交通运输工程学报2002(3).
[49]陆峰.张东亚.张国铭应用神经网络方法确定岩石边坡安全系数2000.
[2]郑颖人,赵尚毅.边坡工程设计中安全系数的讨论[J].岩石力学与工程学报.2006,25(9)：1938-1940.
[3]陕西省宝鸡峡工程指挥部,陕西省宝鸡峡引渭灌溉管理局,陕西省水利电力勘测设计院.宝鸡峡引渭灌溉工程技术总结[M].13-16.
[4]王家臣,洛中洲.关于边坡稳定可靠性分析的几点看法[J].世界煤炭技术.1999,(7)：16-20.
[5]龚宪伟,易念平,张信贵.对边坡工程安全系数的思考[J].广西大学学报.2006,31(3)：265-270.
[6]陈祖煜.土质边坡稳定分析—原理,方法,程序[M].中国水利水电出版社,2003土工程学报.2007,29(1)：147-151.
[7]饶文英,郭增玉.黄土高边坡的滑坡机理与稳定分析方法探讨[J].陕西机械学院学报.1988,4(2)：47-62.
[8]Hovland H. J. Three-dimensional slope stability analysis method[J].Journal of the Geotechnical Engineering, Division Proceed2ings of the American Society of Civil Engineers,1977,103(GT9):971-986.
[9]陈祖煜,张广文.关于“土坡稳定性分析”一文的讨论[J].岩土工程学报,1995,17(6)
[10]刘三仓,隋国秀,刘志伟.非饱和-饱和状态下黄土地基中灌注桩承载性能的研究[J].岩土工程学报.2007,29(1)：147-151.
[11]HungrO,Salgado F.M. Byrne P.M. Evaluation of a three-di2mensional method of slope stability analysis[J].CanadianGeotechnical Journal,1989,(26): 679-686.
[12]HungrO.An extension of Bishop's simp lified method of slope stability analysis to threedimensions[J].Geotechnique,1987,37(1):113-117.
[13]李文广.考虑降雨入渗影响的非饱和土边坡突变失稳的研究[D].西安建筑科技大学硕士学位论文,2004.
[14]卢肇钧等.膨胀力在非饱和土强度理论中的应用[J].岩土工程学报,1997(5)：20-27.
[15]钱家欢,殷宗泽.土工原理与计算[M].中国水利水电出版社(第二版),1997.
[16]王晓峰.降雨入渗对非饱和土边坡稳定性影响的分析[D].西安建筑科技大学硕士论文,2003.
[17]党进谦,郝月清.吸水率对黄土结构强度的影响[D].西北水资源与水工程,1998(2)：15-19.
[18]唐晓松,郑颖人.水位下降过程中超孔隙水压力对边坡稳定性的影响[J].水利水运工程学报,2007(1)：1-6.
[19]D.G弗雷德朗德,H.拉哈尔佐.非饱和土力学[M],中国建筑工业出版社,1997.8.
[20]赵慧丽,马易鲁,非饱和土抗剪强度研究方法的探讨[J]岩土工程技术,2001.3.
[21]Fei Cai,Keioz Ugai.Numerical analysis of the stability of a slope reinforced with piles[J].Soil and Foundations,2000,40(1):73-84.
[22]孙敏.饱和-非饱和渗流影响因素及对土坡稳定性影响研究[D].南京：河海大学.
[23]ZhangX.Three-dimensional stability analysis of concave slopes In plan view[J].Jouornal of Geotechnical Engineering,ASCE,1988,(114):658-671.
[24]陈祖煜,弥宏亮,汪小刚.边坡稳定三维分析的极限平衡方法[J].岩土工程学报.2001,23(5)：524-529.
[25]H. F. Schweiger, G. M. Peschl."Reliability analysis in geotechnics with the random setfinite element method"[J].Computer and Geotechnics.32(2005) 422-435.
[26]Fellenius W Calculation of the stability of earth slope[J].Transactions of 2nd Congress on Large Dams,Washington, D C,1936:445-462.
[27]徐捷,王钊,李未显.非饱和土吸力量测技术[J].岩石力学与工程学报,2000.6.
[28]肖桃李,李新平,米健.土质边坡稳定性影响因素的研究[J].地质灾害与环境保护.
[29]Bishop A W. The use of slip circle in the stability analysis of slopes[J]. Geotechnique,1955,1(1):7-17.
[30]Janbu N. Application of composite slip surface for stability analysis[A]. Proc.,European Conf.on stability of earth slopes[C],Sweden,1954(3), 43-49.
[31]Sanna S K. Stability analysis of embankments and slopes[J].Geotechnical, 1973,23(3):423-33.
[32]Morgenstern N R, Price V E.The analysis of the stability of general slip Surfaces[J]. Geotechnique,1965,15(1),79-3.
[33]Spencer E.A method of analysis of the stability of embankments assuming parallel inter-slice forces[J].Geotechnique,1967,17(1):11-6.
[34]Janbu N. Slope stability computations[A].In:Hirschfield E, Poulos S,Editors, Embankment Dam Engineering[C].New York:John Wiley,1973:47-6.
[35]Chen Zhuyu, Morgenstern N R. Extensions to the generalized method of slices for stability analysis[J].Canadian Geotechnical Journal 1983,20(1): 104-19.
[36]郑颖人,赵尚毅,时卫民,林丽.边坡稳定分析的一些进展[J].地下空间,2001,21(4)：262-271.
[37]Duncan J M. State of the art:limit equilibrium and finite-element Analysis of slope[J].Journal of Geotechnical and Geoenvironmental Engineering, ASCE,1996,122(7):577-596.
[38]陈祖煜.土坡稳定分析原理方法程序[M].中国水利水电出版社,2003239-248.(Chen Zhuyu.Soil slope stability analysis-Theory Method and Programs[M].China Water Power Press,2003,239-248.(in Chinese)). 1988,4(2):47-62.
[39]卢肇钧等.非饱和土的抗剪强度与膨胀压力[J].岩土工程学报,1992(3)：1-8.
[40]党进谦,李靖.非饱和黄土的强度特征[J].岩土工程学报,1997(2)：56-61.
[41]汤连生.从粒间吸力特性再认识非饱和土抗剪强度理论阴.岩土工程学报,2001.
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