砂岩的三维非线性损伤蠕变特性

Three-Dimensional Nonlinear Damage Creep Characteristics of Sandstone

岩石的蠕变性质对预测巷道围岩失稳、保障矿山生产安全等具有重要影响,岩石蠕变本构模型的建立是研究岩石蠕变变形特性的重要依据。针对传统蠕变模型难以反映岩石的加速蠕变阶段特征的问题,提出了一种改进的西原体模型,建立了一个可变黏性系数的黏性元件,用来替代传统西原体模型中的常规黏性元件,并推导出改进后的西原体模型的本构方程和一维、三维蠕变方程。通过不同应力等级下的三轴压缩蠕变试验,采用Origin软件对该模型进行参数辨识及曲线拟合,对比分析实际试验数据与模型参数,结果表明:试验实际数据值与理论计算值吻合度均大于0.93,改进的西原体模型能够准确描述岩石加速蠕变阶段的特征,验证了该模型的正确性和适用性,具有重要的理论意义。

The creep characteristics of rock has an important effect on predicting the instability of surrounding rock and ensuring the safety of mine production.The establishment of rock creep constitutive model is an important basis for studying the creep characteristics of rock.Aiming at the problem that the traditional creep model was difficult to reflect the characteristics of the accelerated creep stage of rock,an improved Nishihara model was proposed.A viscous element with variable viscosity coefficient was established to replace the conventional viscous element in the traditional Nishihara model.The constitutive equation and one-dimensional and three-dimensional creep equations of the improved Nishihara model were derived.Through the triaxial compression creep test under different stress levels,the Origin software was used to identify the parameters and curve fitting of the model,and the actual test data were compared with the model parameters.The results show that the agreement between the actual data value and the theoretical calculation value is greater than O.93,and the improved Nishihara model can accurately describe the characteristics of the accelerated creep stage of rock,which verifies the correctness and applicability of the model and has an important theoretical reference.