酸碱影响下砂岩流变参数识别方法及敏感度

根据长期暴露在自然环境中的砂质岩体易遭受水及可溶离子化学侵蚀作用的事实，通过对相同浓度不同pH值CaCl₂试剂浸泡处理过的砂岩试件进行三轴剪切试验，根据试验结果选取符合试验规律的二阶简化广义Kelvin流变模型，按照定泊松比假设将其变形为三项应力状态。基于搜索模式的最小二乘方法（LSMPS）获取模型参数最优解，以均方根误差评价模型对各参数变化的敏感性程度。采用延迟时间评价砂岩在不同化学环境中达到稳定蠕变过程所需时间。通过搜索模式识别的模型参数能够使模型计算值与加载试验获得的实测值比较接近，表明该模型及其参数识别方法在确定受化学因素干扰下的砂岩流变特征比较适用。

Rheological parameters identification and sensitivity analysis of sandstone under acid and alkali effects

According to the fact that the sandy rock mass exposed to the natural environment is susceptible to water and soluble chemical attack, the triaxial shear test is carried out on sandstone specimens treated with CaCl₂ reagent with different pH value. The second-order simplified generalized Kelvin rheological model conforming to the experimental rule is chosen to deform it into three stress states according to the hypothesis of the Poisson''s ratio. Based on the least squares method (LSMPS) of the search pattern, the optimal solution of the model parameters is obtained, and the sensitivity of the model to the change of the parameters is evaluated by the root mean square error. The delay time is used to evaluate the time required for the sandstone to stabilize the creep process in different chemical environments. The model parameters identified by the search pattern can make the calculated value of the model close to the measured value obtained by the loading test, which indicates that the model and its parameter identification method are suitable for determining the rheological characteristics of the sandstone under the disturbance of chemical factors.