在岩土工程的实践中，许多岩土体材料在载荷作用下表现出应变软化特性，因而在岩土工程数值模拟中如何更好地表现出岩土材料的应变软化特性非常关键。首先分析了“圆形孔洞问题”这一岩土工程领域的基本问题，并对该问题基于应变软化模型建立的现有理论解与FLAC^3D的数值计算结果进行了对比，所得到的结果验证了FLAC^3D应变软化模型在数值计算时的准确性和适用性。接着采用FLAC^3D程序中的应变软化模型与理想弹塑性模型对该问题进行了计算，通过对计算结果的对比分析，认为忽略应变软化岩土材料的强度软化特性对工程是偏于危险的。最后对FLAC^3D中应变软化模型的相关参数(ε^p_i、残余系数 )进行了研究。研究成果有助于研究人员更深入地理解岩石应变软化模型的力学本质。

Many of rock and soil materials exhibit strain softening behavior under load in geotechnical engineering practice. To show the strain softening properties of geotechnical material is crucial in the numerical simulation of geotechnical engineering. Based on previous researches, the authors analyze the circular cavity expansion problem which is one of the basic problems in geotechnical engineering, and compares the results of theoretical solution of strain softening model with FLAC^3D numerical calculations. The comparison confirms  the accuracy and applicability of strain softening model in FLAC^3D numerical calculation. Moreover, the numerical results obtained from computations by strain softening model and elasticperfectly plastic constitutive model are compared. Results show that the strength softening  of strain softening geotechnical materials could not afford to be ignored. Finally, the related parameters (ε^p_i and η ) of strain softening model are analyzed. The research results could help researchers understand the nature of mechanics in strain softening model of rocks in the numerical calculation.