盐岩压剪条件下的损伤特性研究

为了解盐岩在压剪受力状态下的损伤特性，设计了不同放置角度的盐岩压剪试验和声发射信号采集试验，研究了盐岩试件在不同剪切角度下的损伤力学特性和声发射信号特征。针对压剪受力状态，从一般力学模型入手，讨论建立了关于剪应力和正应变的剪切损伤模型。试验结果表明，随放置角度的增大，盐岩的力学特性由塑性为主要特征逐渐转为脆性为主要特征；试验中放置角度越大，盐岩试件峰值剪应力越小，试件整体承载能力也呈下降趋势，试件的变形能力减弱，抗变形能力则随放置角度增大而先增大后减小，45°时达到最大。声发射信号表明，盐岩由于其自身的结构和损伤破坏特征，盐岩在压剪受力状态下的声发射信号比较明显；试件的放置角度为55°、65°时，在屈服阶段AE计数波动相对越剧烈，试件破坏的也越快；试件的放置角度小于45°时，AE计数呈递增式增长，峰值一般出现峰值应力附近。

Research on shear damage properties of salt rock under compression-shear state

In order to understand the shear properties of salt rock under compression-shear state, the compression-shear test and acoustic emission test on salt rock at different insertion angle are designed. The characteristics of damage mechanics and acoustic emission signal for salt rock specimens at different shear angles are studied. In addition, considering the condition of compression and shear, the shear damage model with respect to shear stress and normal strain is established based on general dynamic model. Test results show that, with increase of placed angle, the mechanical characteristics of salt rock shift from plasticity for main features gradually to brittleness for main mechanical features; while the placed angle increases, the peak shear stress of salt rock decreases; the overall capacity of bearing load also shows declined trend; the capacity for deformation weakens with angle increasing and the capacity against deformation with angle increasing strengthens firstly and weakens lastly, reaching the maximum while angle of 45 degree. The acoustic emission test shows that, due to its own structure and damage features, the signal of salt rock under compression-shear state is comparatively apparent; while placed angle is 55 degree and 65 degree, the AE count of specimens in yield stage fluctuates more violently; and the process of break is also more fast; while placed angle is less than 45 degree, the AE count increases gradually; and the peak generally appears near the peak stress.