双强度折减法的配套折减机制
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摘要
双强度折减法考虑了c、φ的不同折减程度,更符合真实情况.采用单独折减tanφ所确定的折减系数R_1和单独折减c所确定的R_2来定义双折减的配套折减系数K=R_1/R_2.分析发现该种定义符合前人所提出的物理、力学机制,从强度参数空间的角度解释了K=R_1/R_2在稳定系数大于1的黏性土质边坡中的合理性.用参数路径的概念分析双强度折减法的本质——强度参数的劣化,并围绕所提出的两个问题进行解释;结合初始强度参数点、临界状态点、折减路径、临界状态的分析,较为细致地分析了该方法计算过程和结果的意义.将4个算例的计算结果与传统强度折减法结果的对比,发现其结果均偏小,误差在5%以内.
Various reduction degrees of c andφare taken into consideration in the double strength reduction method,so that it will even more agree with actual situation.The matching-reduction coefficient K=R_1/R_2 of the double reduction was defined with reduction coefficients R_1 and R_2,which are determined by single reduction of tanφand c,respectively.It was found by analysis that this definition will agree with the physical and mechanical mechanism proposed by predecessors and the reasonableness of K=R_1/R_2 in the case of cohesive soil slop with safety factor greater than unity was explained with view point of strength parameter space and the concept of parameter path was used to analyze the nature of the double strength reduction method-deterioration of strength parameter and an explanation about the presented two questions was given.Combined with the analysis of the initial strength parameter point,critical state point,reduction path,and critic state,the significance of computational process and result of this computation method was analyzed in comparatively detail.It is found by comparing the computation result of 4models to that of traditional strength reduction method that the former will result in less reduction of strength and its error is within the range of 5%.
Various reduction degrees of c andφare taken into consideration in the double strength reduction method,so that it will even more agree with actual situation.The matching-reduction coefficient K=R_1/R_2 of the double reduction was defined with reduction coefficients R_1 and R_2,which are determined by single reduction of tanφand c,respectively.It was found by analysis that this definition will agree with the physical and mechanical mechanism proposed by predecessors and the reasonableness of K=R_1/R_2 in the case of cohesive soil slop with safety factor greater than unity was explained with view point of strength parameter space and the concept of parameter path was used to analyze the nature of the double strength reduction method-deterioration of strength parameter and an explanation about the presented two questions was given.Combined with the analysis of the initial strength parameter point,critical state point,reduction path,and critic state,the significance of computational process and result of this computation method was analyzed in comparatively detail.It is found by comparing the computation result of 4models to that of traditional strength reduction method that the former will result in less reduction of strength and its error is within the range of 5%.
引文
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[5]赵尚毅,郑颖人,张玉芳.极限分析有限元法讲座:Ⅱ有限元强度折减法中边坡失稳的判据探讨[J].岩土力学,2005,26(2):332-336.
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[9]唐芬,郑颖人.基于双安全系数的边坡稳定性分析[J].公路交通科技,2008,25(11):39-44.
[10]BAI Bing,YUAN Wei,LI Xiaochun.A new double reduction method for slope stability analysis[J].Journal of Central South University,2014,21(3):1158-1164.
[11]YUAN Wei,BAI Bing,LI Xiaochun,et al.A strength reduction method based on double reduction parameters and its application[J].Journal of Central South University,2013,20(9):2555-2562.
[12]白冰,袁维,石露,等.一种双折减法与经典强度折减法的关系[J].岩土力学,2015,36(5):1275-1281.
[13]梁庆国,李德武.对岩土工程有限元强度折减法的几点思考[J].岩土力学,2008,29(11):3053-3058.
[14]朱彦鹏,杨晓宇,叶帅华,等.双强度折减法的量化分析[J].冰川冻土,2016,38(4):880-888.
[15]赵尚毅,郑颖人,张玉芳.有限元强度折减法中边坡失稳的判据探讨[J].岩土力学,2005,26(2):332-336.
[16]程东幸,刘大安,丁恩保,等.滑带土长期强度参数的衰减特性研究[J].岩石力学与工程学报,2005,24(增刊2):5827-5834.
[2]GRIFFTHS D V,LANE P A.Slope stability analysis by finite elements[J].Geotechnique,1999,49(3):59-70.
[3]郑颖人,赵尚毅.有限元强度折减法在土坡与岩坡中的应用[J].岩石力学与工程学报,2004,23(19):3381-3388.
[4]赵尚毅,郑颖人,时卫民,等.用有限元强度折减法求边坡稳定安全系数[J].岩土工程学报,2002,24(3):343-346.
[5]赵尚毅,郑颖人,张玉芳.极限分析有限元法讲座:Ⅱ有限元强度折减法中边坡失稳的判据探讨[J].岩土力学,2005,26(2):332-336.
[6]唐芬,郑颖人.边坡稳定安全储备的双折减系数推导[J].重庆交通大学学报(自然科学版),2007,26(4):95-100.
[7]唐芬,郑颖人,赵尚毅.土坡渐进破坏的双安全系数讨论[J].岩石力学与工程学报,2007,26(7):1402-1407.
[8]唐芬,郑颖人.边坡渐进破坏双折减系数法的机理分析[J].地下空间与工程学报,2008,4(3):436-441.
[9]唐芬,郑颖人.基于双安全系数的边坡稳定性分析[J].公路交通科技,2008,25(11):39-44.
[10]BAI Bing,YUAN Wei,LI Xiaochun.A new double reduction method for slope stability analysis[J].Journal of Central South University,2014,21(3):1158-1164.
[11]YUAN Wei,BAI Bing,LI Xiaochun,et al.A strength reduction method based on double reduction parameters and its application[J].Journal of Central South University,2013,20(9):2555-2562.
[12]白冰,袁维,石露,等.一种双折减法与经典强度折减法的关系[J].岩土力学,2015,36(5):1275-1281.
[13]梁庆国,李德武.对岩土工程有限元强度折减法的几点思考[J].岩土力学,2008,29(11):3053-3058.
[14]朱彦鹏,杨晓宇,叶帅华,等.双强度折减法的量化分析[J].冰川冻土,2016,38(4):880-888.
[15]赵尚毅,郑颖人,张玉芳.有限元强度折减法中边坡失稳的判据探讨[J].岩土力学,2005,26(2):332-336.
[16]程东幸,刘大安,丁恩保,等.滑带土长期强度参数的衰减特性研究[J].岩石力学与工程学报,2005,24(增刊2):5827-5834.