考虑软岩参数随时间变化的非定常西原蠕变模型参数辨识及数值模拟

Parameter Identification and Numerical Simulation of Unsteady Nishihara Creep Model Considering Changes of Soft Rock Parameters with Time

为了准确地描述软岩蠕变规律,基于经典西原模型,考虑软岩参数随时间的变化,建立一种非定常西原模型,并采用单轴压缩蠕变试验研究软岩的蠕变力学特性,基于单轴压缩蠕变试验数据对所建立模型进行参数辨识;利用ABAQUS软件的二次开发功能,将所建立模型嵌入其中进行软岩蠕变过程的数值模拟。结果表明:通过拟合单轴压缩蠕变试验数据并辨识相关参数,相关系数不小于0.997,所建立模型与实际情况吻合度较高,可准确地描述软岩的初期蠕变、等速蠕变、加速蠕变3个阶段;模拟结果与单轴压缩蠕变试验结果基本吻合,验证了所建立模型可以在数值软件中准确应用并进行相关工程计算。

To accurately describe creep law of soft rocks,on the basis of classical Nishihara model and considering changes of soft rock parameters with time,an unsteady Nishihara model was established,and creep mechanical properties of soft rocks were researched by using uniaxial compression creep tests.On the basis of uniaxial compression creep test data,the parameters of the established model were identified.Using the secondary development function of ABAQUS software,the established model was embedded into the software to numerically simulate creep process of soft rocks.The results show that the correlation coefficient of the fitting curve is not less than or equal to 0.997 through fitting of uniaxial compression creep test data and parameter identification.The established model has high fitting accuracy and can accurately describe the three soft rock creep stages of initial creep,constant velocity creep,and accelerated creep.The simulation results are basically consistent with the uniaxial compression creep test results,which verifies that the established model can be accurately used in the numerical software and related engineering calculations.