卤水浸泡后盐岩声发射特征试验研究

Study of acoustic emission character of salt rock soaked in brine

为了研究盐穴能源地下储库建造过程中,腔体围岩处在地温、卤水和地应力地质环境中盐岩的损伤演化特点,利用声发射技术分析盐岩受不同温度的饱和卤水作用后的单轴压缩损伤破坏过程。试验发现:在一定温度的饱和卤水中浸泡30 d后盐岩的单轴抗压强度和弹性模量有所降低,但降低的平均幅度很小;卤水对盐岩主要表现为溶蚀作用,而浸泡弱化作用非常小;单轴压缩过程中盐岩的应力-应变曲线与声发射-应变曲线具有较好的一致性,卤水浸泡后盐岩的累计声发射数随卤水的温度升高略有增加;卤水作用后盐岩试件的声发射率和累计数要小于无卤水作用盐岩;盐穴建造期盐岩受一定温度的卤水作用后盐岩的强度将出现一定弱化,但卤水也会促进损伤盐岩体的重结晶恢复,盐岩的这种特性有利于盐穴建造期安全和稳定。

In order to study the salt rock damage evolution characteristics in a certain ground temperature,brine and ground stress of the geological environment during the construction process of energy underground storage,the acoustic emission（AE） method is used to analyze the uniaxial compression damage process of salt rock with the combined effect of temperature and saturated brine.It is found that the uniaxial compressive strength and elastic modulus of salt rock samples are slightly lower after soaked in brine for 30 days.The changed peak strength of salt rock caused by saturated brine is not obvious.It is means that brine mainly works on dissolution effect on salt rock while with little soak weakening effect.The stress-strain curves and the acoustic emission-strain curves of salt rock have good consistency in the process under uniaxial compression tests;and the cumulative AE number increases with the increasing brine temperature.The salt rock samples soaked in the brine are usually with lower AE rate and AE number after the temperature and brine actions.In the construction period of salt cavern,salt rocks may lose slightly the strength but gain damage recovery due to brine.This feature of salt rock is conducive to security and stability during salt cavern construction.