围压作用下盐岩损伤恢复研究

为了解在围压作用下盐岩损伤恢复特性和盐岩损伤与强度之间的联系，设计了盐岩在不同围压、不同稳压时间之后盐岩强度测试试验。试验结果表明：加载初期，盐岩弹性模量随着稳压时间的增大而逐渐增大，且随着稳压时间的增大，盐岩峰值应力对应的轴向应变和横向应变均会逐渐增大；盐岩损伤与强度之间存在负相关联系；随着稳围压时间的增加，盐岩强度逐渐增大，最后保持在趋于相对稳定的状态；在围压作用下盐岩损伤愈合可以分为损伤快速恢复阶段和损伤缓慢恢复阶段，且对于不同稳压大小，盐岩损伤恢复两个阶段有明显的时间节点；在一定范围内，盐岩损伤快速恢复阶段的时间长短随着稳压阶段围压的增大而逐渐减小；增加稳围压阶段的围压大小可以一点程度上缩短盐岩损伤快速恢复阶段时间，但是增大围压可能会对盐岩造成新的损伤。

Study of damage recovery of salt rock under confining pressures

In order to understand salt rock damage recovery characteristics and the connection of damage and strength under the effect of confining pressure. Different test has been designed for salt rock with different confining pressure and different holding time of confining pressure. The results showed that at early loading, the salt rock elastic modulus increases gradually along with the increase of the pressure holding time, and with the increase of pressure holding time, the corresponding axial strain and lateral strain of salt rock peak stress will increase gradually. There is a negative correlation between salt rock damage and strength .With the increasing of holding time of confining pressure the intensity of salt rock gradually increasing, and finally tends to maintain a relatively stable state. The damage recovery of salt rock can be divided into rapid damage recovery phase and slow damage recovery phase under the effect of confining pressure, and there is a distinct time node for different salt rock damage recovery phase. Within a certain range, with the increasing of the strength of confining pressure in the stage of holding confining pressure, the duration of salt rock rapid damage recovery phase is gradually reduced. The duration of salt rock rapid damage recovery phase can be shorten with the increasing of the strength of confining pressure in the stage of holding confining pressure. However, with the increasing the strength of confining pressure, new damage may be caused in the salt rock.