三轴循环加卸载过程中盐岩声发射演化特征分析

发布时间：2018-08-02 13:27

【摘要】：为探究盐岩储气库运行过程中的声发射特征,对取自平顶山岩穴一号钻孔的盐岩进行不同围压作用下的三轴循环加卸载试验及全过程声发射监测试验。试验研究表明:围压施加过程中,声发射信号主要出现在围压施加前期,声发射振铃计数率和能量率的最大值出现在围压压力5~10 MPa的时间区段,且振铃计数率和能量率达到最大以后,声发射信号随着围压的增大逐渐减弱;围压越低,试验加载初期产生的声发射信号越强,整个试验过程中累积振铃计数越多,能量率和能量越高;围压会使试验过程中声发射信号后移,且围压越大,后移现象越明显;围压的增大会使得盐岩加载过程中的平静期缩短和后移,直至平静期的消失;考虑三轴加卸载过程,加载段有明显的声发射信号,卸载段鲜有声发射信号,偏应力峰值前有明显的Kaiser现象,峰值后伴随大量的声发射信号,但Kaiser现象消失。
[Abstract]:In order to investigate the characteristics of acoustic emission during the operation of the salt reservoir, the triaxial cyclic loading and unloading test and the whole process acoustic emission monitoring test were carried out on the salt rock from the No. 1 borehole of Pingdingyan Cave under different confining pressures. The experimental results show that the acoustic emission signal mainly appears in the early stage of the confining pressure, and the maximum of the counting rate and energy rate of the acoustic emission ring appears in the time range of 5 ~ 10 MPa of the confining pressure. When the ring counting rate and energy rate reach the maximum, the acoustic emission signal decreases with the increase of the confining pressure, the lower the confining pressure, the stronger the acoustic emission signal produced at the initial loading stage, and the more the cumulative ring count is during the whole test. The higher the energy rate and energy is, the more the confining pressure will cause the acoustic emission signal to move backward, and the larger the confining pressure, the more obvious the backward shift phenomenon is, and the larger the confining pressure is, the shorter and backward the quiet period will be during the loading of salt rock, until the quiet period will disappear. Considering the triaxial loading and unloading process, there are obvious acoustic emission signals in the loading section, few acoustic emission signals in the unloading section, and obvious Kaiser phenomenon before the peak deflection stress, followed by a large number of acoustic emission signals after the peak value, but the Kaiser phenomenon disappears.
【作者单位】：四川大学水力学与山区河流开发保护国家重点实验室;四川省水利水电勘测设计研究院;
【基金】：国家自然科学基金(513741481;51641405) 四川省青年科技基金(2017JQ0003)
【分类号】：TU45

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