Drucker-Prager准则参数特性分析

STUDY ON PARAMETRIC CHARACTERS OF DRUCKER-PRAGER CRITERION

Drucker-Prager准则在数值计算中得到广泛运用。但如果该准则的参数选取不当,可能导致预测与试验结果之间不一致。通过分析函数基本特性,考察该准则反映中主应力对强度参数影响的能力,探讨导致预测与试验结果之间不一致的可能原因。进而对目前常用的参数表达式进行详细的分析,并考察平面应变情况下Drucker-Prager准则的参数特性。分析表明:Drucker-Prager准则不能合理地反映中主应力对强度参数的影响,且在平面应变情况下会得出中主应力系数小于0的结论。

Drucker-Prager criterion has been widely used in geotechnical engineering.However,in some cases,the numerical result with Drucker-Prager criterion will be not consistent with the testing result,especially when the parameters are not selected appropriately from tests.In this paper,the parametric characters of Drucker-Prager criterion are analyzed with mathematic methods.Some possible reasons leading to the inconsistentness are studied.Moreover,based on the Drucker-Prager criterion,the strength parameters of different intermediate principal stresses are generally compared.It is demonstrated that the intermediate principal stresses′ effects can not be reasonably reflected with those parameters to a certain degree.Furthermore,an unreasonable result that the coefficient of the intermediate principal stress is little than 0 is achieved under the condition of plane strain with the Drucker-Prager criterion.