土坡稳定分析中考虑参数变异水平的分项系数取值
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摘要
岩土参数变异性大导致可靠指标离散性高,仅用1组分项系数难以保证土工结构可靠性达到目标可靠度。将土体强度参数变异性划分为小、中、大3个水平,以现有规范规定安全系数为控制指标,对常见铁路路堤边坡目标可靠度进行校准,确定目标可靠指标为2.3;运用验算点法计算分项系数,讨论几何和强度参数对分项系数影响规律,通过统计分析及标定得到了对应3种变异水平的分项系数推荐值。研究结果表明:土体强度参数变异性是影响分项系数取值的主导因素,强度参数均值和坡高次之,坡率的影响较为微弱;为使强度参数变异性不同的边坡达到一致的可靠度,提出了分项系数应与参数变异水平相适应的取值原则,给出了小、中、大变异水平对应的抗力项和荷载项分项系数(γR1,γR2,γS)推荐值分别为(0.75, 0.95; 1.02),(0.55, 0.90; 1.06)和(0.40, 0.80; 1.10)。
Large variation of geotechnical property result in large discrete of engineering reliability index,reliability index of engineering can not achieve our goals by single partial factors,The variability of soil strength parameter was divided into three grades:small,medium and large,a series of simple slope models with a variety of geometric and intensity parameters was constructed based on the calibration method and carrying out stable reliability calculation,and determine the target reliability index is 2.3.Calculating the partial factors by design point method,the influence of soil strength parameters and slope geometric parameters on the partial factor was discussed,and the recommended values of the partial factors under the three variation levels were calculated by the design point method.Study shows that the coefficient of variation of soil strength parameters is the dominant factor for the partial factors,mean value of soil strength parameters and slope height also have a certain impact on the partial factors,the effect of slope rate on partial factors is small;In order to make the slope with different variation of strength parameters to achieve consistent reliability,value principle is proposed partial factors should be adapted to the level of parameters variation,and the recommended values of the resistance term and the load term of the partial factors with small,medium,and large parameter variation level are(0.75,0.95,1.02),(0.55,0.90,1.06),(0.40,0.80,1.10).
Large variation of geotechnical property result in large discrete of engineering reliability index,reliability index of engineering can not achieve our goals by single partial factors,The variability of soil strength parameter was divided into three grades:small,medium and large,a series of simple slope models with a variety of geometric and intensity parameters was constructed based on the calibration method and carrying out stable reliability calculation,and determine the target reliability index is 2.3.Calculating the partial factors by design point method,the influence of soil strength parameters and slope geometric parameters on the partial factor was discussed,and the recommended values of the partial factors under the three variation levels were calculated by the design point method.Study shows that the coefficient of variation of soil strength parameters is the dominant factor for the partial factors,mean value of soil strength parameters and slope height also have a certain impact on the partial factors,the effect of slope rate on partial factors is small;In order to make the slope with different variation of strength parameters to achieve consistent reliability,value principle is proposed partial factors should be adapted to the level of parameters variation,and the recommended values of the resistance term and the load term of the partial factors with small,medium,and large parameter variation level are(0.75,0.95,1.02),(0.55,0.90,1.06),(0.40,0.80,1.10).
引文
[1]Phoon K K,Kulhawy F H.Characterization of geotechnical variability[J].Canadian Geotechnical Journal,1999,36(4):612-624.
[2]Akbas S O,Kulhawy F H.Characterization and estimation of geotechnical variability in ankara clay:a case history[J].Geotechnical and Geological Engineering,2010,28(5):619-631.
[3]Sina J,Richard J B.Simplified probabilistic slope stability design charts for cohesive and cohesive-frictional soils[J].Journal of Canadian Geotechnical,2014,(51):1033-1045.
[4]WU T H,Kraft L M.Safety analysis of slopes[J].Journal of the Soil Mechanics and Foundations Division,1970,96(2):609-630.
[5]郭重凤.国际工程中外设计差异分析及应对策略研究[J].铁道工程,2017,34(7):1-4.GUO Chongfeng.Design difference analysis and coping strategies for international project[J].Journal of Railway Engineering Society,2017,34(7):1-4.
[6]王仲锦,吴敏敏,程爱君,等.铁路路堤边坡的可靠度设计方法研究[J].铁道工程学报,2013(3):24-27.WANG Zhongjin,WU Minmin,CHENG Aijun,et al.Study on design method for slope reliability of railway embankment[J].Journal of Railway Engineering Society,2013(3):24-27.
[7]张宁,李旭,储昭飞,等.关于土坡稳定分析中的分项系数取值讨论[J].岩土工程学报,2015,38(9):1695-1704.ZHANG Ning,LI Xu,CHU Zhaofei,et al.Discussion on the optimum partial factor values in the stability analysis of soil slope[J].Chinese Journal of Geotechnical Engineering,2015,38(9):1695-1704.
[8]吴兴正,蒋良潍,罗强,等.路堤边坡稳定可靠度计算中的模型不确定性分析[J].岩土力学,2015,36(增2):665-672.WU Xingzheng,JIANG Liangwei,LUO Qiang,et al.Analysis of model uncertainty for stability reliability of embankment slope[J].Rock and Soil Mechanics,2008,36(Suppl 2):665-672.
[9]Q/CR 9127-2015,铁路路基极限状态法设计暂行规范[S].Q/CR 9127-2015,Interim code for limit state design of railway earth structure[S].
[10]张继周,缪林昌,陈俊波.苏中腹地湖相软土土性参数变异性统计描述[J].岩土力学,2010,31(2):471-477.ZHANG Jizhou,MIAO Linchang,CHEN Junbo.Statistical characterization of variability of lacustrine soft soil in central region of Jiangsu province[J].Rock and Soil Mechanics,2010,31(2):471-477.
[11]Roh Gwangha,HONG H P.Calibration of information-sensitive partial factors for assessing earth slopes[J].Journal of Geoengineering,2009,4(3):95-96.
[12]CEN(European Committee for Standardization).EN1997-1,Eurocode7:Geotechnical Design--Part 1[S].Brussels,2004.
[13]高大钊.地基土力学性质指标的可靠性分析与取值[J].同济大学学报(自然科学版),1985,25(4):59-68.GAO Dazhao.The reliability of the mechanics properties of foundation soil index analysis and value[J].Journal of Tongji University(Natural Science),1985,25(4):59-68.
[14]李小勇.土工参数空间概率特性及软黏土地基固结概率分析[D].杭州:浙江大学,2001.LI Xiaoyong.Spatial probabilistic characteristics of geotechnical parameters and probability analysis of consolidation of soft clay ground[D].Hangzhou:Zhejiang University,2001.
[15]聂士诚.土质边坡稳定的可靠度分析及其土性参数的敏感性研究[D].长沙:中南大学,2002.NIE Shicheng.Reliability analysis of slope stability and research on sensitivity of soil parameters[D].Changsha:Central South University,2002.
[16]陈善攀.土质边坡稳定可靠度分析遗传算法方法及程序设计[D].长沙:中南大学,2008.CHEN Shanpan.Genetic algorithm method and program design for reliability analysis of soil slope stability[D].Changsha:Central South University,2008.
[17]EL-RAMLY H.Probabilistic analyses of landslide hazards and risks:bridging theory and practice[D].Alta:University of Alberta,Edmonton,2001.
[18]GB 50216-94,铁路工程结构可靠度设计统一标准[S].GB 50216-94,Unified design standard for reliability of railway engineering structures[S].
[19]TB10001-2015,铁路路基设计规范[S].TB10001-2015,Code for design on subgrade of railway[S].
[20]骆飞,罗强,蒋良潍,等.土体抗剪强度指标变异水平对边坡稳定安全系数取值的影响[J].土木建筑与环境工程,2015,37(4):77-83.LUO Fei,LUO Qiang,JIANG Liangwei,et al.Influence of variation levels of soil strength indexes on the value of slope stability factor[J].Journal of Civil,Architectural&Environmental Engineering,2015,37(4):71-83.
[21]GB 50199-2013,水利水电工程结构可靠性设计统一标准[S].GB 50199-2013,Unified design standard for reliability of hydraulic engineering structures[S].
[22]张文生,罗强,蒋良潍,等.边坡稳定分析中岩土参数置信水平取值探讨[J].铁道科学与工程,2017,14(4):697-704.ZHANG Wensheng,LUO Qiang,JIANG Liangwei,et al.Value of confidence level for geotechnical parameters in slope stability analysis[J].Journal of Railway Science and Engineering,2017,14(4):697-704.
[2]Akbas S O,Kulhawy F H.Characterization and estimation of geotechnical variability in ankara clay:a case history[J].Geotechnical and Geological Engineering,2010,28(5):619-631.
[3]Sina J,Richard J B.Simplified probabilistic slope stability design charts for cohesive and cohesive-frictional soils[J].Journal of Canadian Geotechnical,2014,(51):1033-1045.
[4]WU T H,Kraft L M.Safety analysis of slopes[J].Journal of the Soil Mechanics and Foundations Division,1970,96(2):609-630.
[5]郭重凤.国际工程中外设计差异分析及应对策略研究[J].铁道工程,2017,34(7):1-4.GUO Chongfeng.Design difference analysis and coping strategies for international project[J].Journal of Railway Engineering Society,2017,34(7):1-4.
[6]王仲锦,吴敏敏,程爱君,等.铁路路堤边坡的可靠度设计方法研究[J].铁道工程学报,2013(3):24-27.WANG Zhongjin,WU Minmin,CHENG Aijun,et al.Study on design method for slope reliability of railway embankment[J].Journal of Railway Engineering Society,2013(3):24-27.
[7]张宁,李旭,储昭飞,等.关于土坡稳定分析中的分项系数取值讨论[J].岩土工程学报,2015,38(9):1695-1704.ZHANG Ning,LI Xu,CHU Zhaofei,et al.Discussion on the optimum partial factor values in the stability analysis of soil slope[J].Chinese Journal of Geotechnical Engineering,2015,38(9):1695-1704.
[8]吴兴正,蒋良潍,罗强,等.路堤边坡稳定可靠度计算中的模型不确定性分析[J].岩土力学,2015,36(增2):665-672.WU Xingzheng,JIANG Liangwei,LUO Qiang,et al.Analysis of model uncertainty for stability reliability of embankment slope[J].Rock and Soil Mechanics,2008,36(Suppl 2):665-672.
[9]Q/CR 9127-2015,铁路路基极限状态法设计暂行规范[S].Q/CR 9127-2015,Interim code for limit state design of railway earth structure[S].
[10]张继周,缪林昌,陈俊波.苏中腹地湖相软土土性参数变异性统计描述[J].岩土力学,2010,31(2):471-477.ZHANG Jizhou,MIAO Linchang,CHEN Junbo.Statistical characterization of variability of lacustrine soft soil in central region of Jiangsu province[J].Rock and Soil Mechanics,2010,31(2):471-477.
[11]Roh Gwangha,HONG H P.Calibration of information-sensitive partial factors for assessing earth slopes[J].Journal of Geoengineering,2009,4(3):95-96.
[12]CEN(European Committee for Standardization).EN1997-1,Eurocode7:Geotechnical Design--Part 1[S].Brussels,2004.
[13]高大钊.地基土力学性质指标的可靠性分析与取值[J].同济大学学报(自然科学版),1985,25(4):59-68.GAO Dazhao.The reliability of the mechanics properties of foundation soil index analysis and value[J].Journal of Tongji University(Natural Science),1985,25(4):59-68.
[14]李小勇.土工参数空间概率特性及软黏土地基固结概率分析[D].杭州:浙江大学,2001.LI Xiaoyong.Spatial probabilistic characteristics of geotechnical parameters and probability analysis of consolidation of soft clay ground[D].Hangzhou:Zhejiang University,2001.
[15]聂士诚.土质边坡稳定的可靠度分析及其土性参数的敏感性研究[D].长沙:中南大学,2002.NIE Shicheng.Reliability analysis of slope stability and research on sensitivity of soil parameters[D].Changsha:Central South University,2002.
[16]陈善攀.土质边坡稳定可靠度分析遗传算法方法及程序设计[D].长沙:中南大学,2008.CHEN Shanpan.Genetic algorithm method and program design for reliability analysis of soil slope stability[D].Changsha:Central South University,2008.
[17]EL-RAMLY H.Probabilistic analyses of landslide hazards and risks:bridging theory and practice[D].Alta:University of Alberta,Edmonton,2001.
[18]GB 50216-94,铁路工程结构可靠度设计统一标准[S].GB 50216-94,Unified design standard for reliability of railway engineering structures[S].
[19]TB10001-2015,铁路路基设计规范[S].TB10001-2015,Code for design on subgrade of railway[S].
[20]骆飞,罗强,蒋良潍,等.土体抗剪强度指标变异水平对边坡稳定安全系数取值的影响[J].土木建筑与环境工程,2015,37(4):77-83.LUO Fei,LUO Qiang,JIANG Liangwei,et al.Influence of variation levels of soil strength indexes on the value of slope stability factor[J].Journal of Civil,Architectural&Environmental Engineering,2015,37(4):71-83.
[21]GB 50199-2013,水利水电工程结构可靠性设计统一标准[S].GB 50199-2013,Unified design standard for reliability of hydraulic engineering structures[S].
[22]张文生,罗强,蒋良潍,等.边坡稳定分析中岩土参数置信水平取值探讨[J].铁道科学与工程,2017,14(4):697-704.ZHANG Wensheng,LUO Qiang,JIANG Liangwei,et al.Value of confidence level for geotechnical parameters in slope stability analysis[J].Journal of Railway Science and Engineering,2017,14(4):697-704.