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中南大学学报(自然科学版)

Journal of Central South University

第51卷    第2期    总第306期    2020年2月

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文章编号:1672-7207(2020)02-0399-12
Mohr-Coulomb准则的试验验证与修正
曹艺辉,李铀

(中南大学 土木工程学院,湖南 长沙,410075)

摘 要: 利用真三轴试验数据,检验Mohr-Coulomb准则对岩土材料的适用性,讨论并确定一种已有形状函数的模型参数,并利用该形状函数对Mohr-Coulomb准则进行修正,以试验为基础提出黏结力c和内摩擦角 的动态计算式及考虑材料拉压差异的拉压强度比K计算式。研究结果表明:Mohr-Coulomb准则对岩土材料的适用性较差,只能在一定三轴压缩条件下对压缩试验点进行预测,对拉伸强度试验点的预测性差;K越小,模型参数m对Van Eekelen形状函数的影响越大,当m=-0.23时,该形状函数的外凸性最优;修正后的Mohr-Coulomb准则对岩土材料的适用性较好,极限迹线变化规律与试验规律相符,对K预测精确;基于试验结果对c和 的动态计算是可行的,考虑参数的变化能使修正后Mohr-Coulomb准则对岩土材料强度预测更精确,也说明非线性准则优于线性准则;修正的K计算式为静水应力p的单值函数,通过与修正的Lade-Duncan准则、峰值比法计算的K比较,考虑拉压差异的非线性计算方法更优。

 

关键词: Mohr-Coulomb准则;真三轴试验;材料参数;形状函数;拉压强度比K

Test verification and modification of Mohr-Coulomb criterion
CAO Yihui, LI You

School of Civil Engineering, Central South University, Changsha 410075, China

Abstract:The true triaxial test data were used to test the applicability of the Mohr-Coulomb criterion to geotechnical materials. A model parameter of an existing shape function was discussed and determined. The shape function was used to modify the Mohr-Coulomb criterion. A dynamic calculation formula for the bonding force c and friction angle and a calculation formula for the tension-compression ratio K considering the difference between the tension and compression of the materials were proposed. The results show that the Mohr-Coulomb criterion has limited applicability to geotechnical materials and can only be consistent with the experimental law under triaxial compression conditions, and has poor predictability for tensile strength test points. The smaller the K, the greater the influence of model parameter m on the Van Eekelen shape function, and the shape function has the best convexity when m=-0.23. The modified Mohr-Coulomb criterion has good applicability to geotechnical materials, and the envelope variation law is consistent with the experimental law, and the prediction of K is accurate. Dynamic parameter calculation of and based on test results is feasible. Considering the change of parameters, the modified Mohr-Coulomb criterion can predict the strength of geomaterials more accurately, and nonlinear criteria is better than linear criteria. The modified K is a single-valued function of hydrostatic stress p. Compared with the values calculated by the modified Lade-Duncan criterion and peak ratio method, the nonlinear calculation method considering the difference of tension strength and pressure strength is better.

 

Key words: Mohr-coulomb criterion; true triaxial test; material parameters; shape function; aspect ratio of K

中南大学学报(自然科学版)
  ISSN 1672-7207
CN 43-1426/N
ZDXZAC
中南大学学报(英文版)
  ISSN 2095-2899
CN 43-1516/TB
JCSTFT
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