三角波卸载段作用下钙质砂岩毫秒量级变形速率预测模型研究

针对现阶段岩体循环加载下力学响应研究中的不足之处，以宜昌地区钙质中-细砂岩为研究对象和以RMT-150C岩土力学试验系统为试验平台，开展了毫秒(ms)量级三角波卸载段变形速率预测率模型研究。将卸载过程分为非滞后时间段和滞后时间段，给出各段判别依据，提出所需相关参数。定量指出滞后时间段带来的影响，给出滞后时间段的预测模型。在非滞后时间段提出表观弹性模量的概念，试验数据分析表明未出现加载破坏前，岩样表观弹性模量和即时垂向力始终保持线性关系。在该基础上建立三角波卸载段非滞后时间段的变形速率预测率模型模型，由于加载仪器不能精确输入三角波，将加载速率平均值修正和载荷速率中加入常数项修正后，该模型的预测变形速率和应力-应变曲线与实测值精确吻合，表明所建模型的合理性。

Study of prediction model for milliseconds deformation rate in triangular wave unloading segment of calcareous sandstone

In light of that the, studies of mechanical response of rock under cyclic loading need to be more perfected, taking Yichang sandstone as the research object and using the geotechnical testing system RMT-150C for the test platform, the research on the prediction model of deformation rate in triangular wave unloading segment with the magnitude of ms., is carried out. Unloading process is divided into non-lag and lag time segment; and the required parameters and discrimination basis for each segment is given. Effect of lag time segment is pointed out quantitatively; and the prediction mode in time lag segment is also given. Then the concept of the apparent modulus of elasticity in the lag non-lag time segment is proposed; analysis of the test data shows linear relationship between the apparent elastic modulus of the rock sample before the sample was damaged under loading. On this basis, a prediction model of deformation rate by triangular wave unloading in non-lag time segment is established. As the test platform can not be accurately input triangular wave, after the average loading rate and loading rate is corrected by adding corrected constant term, the predicted deformation rate and stress-strain curves of the model are coincide precisely with the measured values, so as to indicate the rationality of the model.