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强度折减法改进及在边坡稳定性评价中的应用

闫云明,崔树军,刘见宝   

  • 出版日期:2017-04-15 发布日期:2017-04-15

Modification of strength reduction FEM and application in slope stability evaluation

YAN Yunming, CUI Shujun, LIU Jianbao   

  • Online:2017-04-15 Published:2017-04-15

摘要: 传统有限元强度折减法在对岩土体强度参数进行折减时并未考虑其对变形参数(弹性模量和泊松比)的影响,会使得分析计算结果不准确,为此改进了传统强度折减法并将其应用于边坡稳定性分析中。基于Mohr-Coulomb强度准则和Duncan-Chang双曲线弹性本构模型,并深入分析土体应力状态、强度与变形的联系,分别建立弹性模量、泊松比与强度折减系数的关系表达式。据此在强度参数折减的同时,对弹性模量和泊松比同时进行修正。以均质土体边坡为例,应用改进的强度折减法开展稳定性评价,并与极限平衡法(Spencer法)进行对比。结果表明:4种有限元强度折减法准确性由大到小依次为:同时修正μ和E方法,只修正E方法,传统有限元强度折减法,只修正μ方法,结论验证了提出的改进方法的合理性和有效性。

关键词: 强度折减法, 有限元, 变形参数修正, 边坡稳定性

Abstract: To consider the influence of deformation parameters, such as elasticity modulus and Poisson's ratio, in reducing strength parameters of rocks and soils, the traditional strength reduction finite element method is modified and applied to slope stability analysis. On the basis of Mohr-Coulomb criteria and Duncan-Chang hyperbolic constitutive model, and by analyzing relationships among the stress state, shear strength and deformation of soils, the expressions of elasticity modulus and Poisson's ratio against strength reduction parameters are respectively derived. According to the proposed formulas, the two deformation parameters are modified in parallel with reduction of strength parameters. The modified method is applied to the stability analysis of a homogeneous soil slope and the results are compared with that of the limit equilibrium method. It shows that the accuracy of the 4 FEM reduction methods rank in a descending order of correcting both μ and E, correcting E only, traditional strength reduction FEM, and correcting μ only, so the proposed method is verified to be reasonable and effective. 〖WT5”HZ〗Key words:〓〖WT5”BZ〗〖ZK(〗strength reduction method; finite element method; correction of deformation parameter; slope stability

Key words: strength reduction method, finite element method, correction of deformation parameter, slope stability