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为了深入研究脆性岩石的渐进破坏过程,利用RMT-150C型岩石力学试验系统对产自鲁南地区的一种红砂岩进行了系统的力学性质试验研究,得出该类型砂岩试样在不同应变率条件下的力学表现。将试件的渐进破坏过程通过特征应力分为裂纹闭合阶段、线弹性变形阶段、裂纹起裂和稳定扩展阶段以及裂纹不稳定扩展阶段,通过对应力-应变曲线、轴向变形刚度、体积应变曲线和裂纹体积应变等数据的分析,以及采用动点回归技术确定了试样的起裂应力和致损应力,并进一步研究了该类红砂岩的渐进破坏过程及红砂岩峰值强度、起裂应力等参数和应变率之间的关系。试验结果表明,随着应变率的增加,红砂岩试样的峰值强度先降低后提高,起裂应力及致损应力与峰值强度的比值均有所降低。分析了红砂岩峰值强度变化的物理机制并给出了解释,研究了应变率对红砂岩渐进破坏过程的影响。
In order to further study the gradual failure process of brittle rocks, a systematic study of the mechanical properties of a red sandstone from the Lunnan area was conducted using the RMT-150C rock mechanics test system. Mechanical performance under conditions. The gradual failure process of specimens is divided into three stages: crack closing stage, linear elastic deformation stage, crack initiation and stable expansion stage, and unstable crack propagation stage. Through the analysis of stress-strain curve, axial deformation stiffness and volume strain curve And crack volume strain and other data analysis, as well as the use of dynamic point of return to determine the sample’s initiation stress and damage stress, and further study of such red sandstone progressive failure process and red sandstone peak strength, cracking stress Relationship between parameters and strain rate. The experimental results show that with the increase of strain rate, the peak intensity of red sandstone sample first decreases and then increases, and the ratio of cracking stress to peak stress decreases. The physical mechanism of red sandstone peak intensity change is analyzed and the explanation is given. The effect of strain rate on the gradual destructive process of red sandstone is studied.