煤岩渗流—蠕变耦合作用下声发射试验研究

发布时间：2018-08-02 13:23

【摘要】：为研究煤岩在渗流—蠕变耦合作用下的声发射及损伤特性,进行了4组不同渗透水压和围压的蠕变声发射测试实验。研究结果表明:累计渗流量曲线对应于蠕变应变曲线,可分为初始、稳态、加速3个阶段;受渗流和蠕变作用的相互影响,在相同围压下,渗透压越大,煤岩的瞬时应变量越大,蠕变速率越高,渗流量越大,声发射越活跃;在相同渗透压下,围压越大,煤岩的瞬时应变量越小,蠕变速率越低,渗流量越小,声发射活跃程度降低;声发射在渗流—蠕变全过程中,整体呈U型变化特征,在体积压缩向体积扩容转变期,声发射异常活跃,表明煤岩此时处于内部结构的调整和损伤状态的转变期;基于Weibull分布函数的损伤表明,各围压下煤岩均存在一个损伤阈值,当损伤超过此值时,煤岩进入加速蠕变变形阶段,且损伤阈值有随围压升高而增大的趋势。
[Abstract]:In order to study the acoustic emission and damage characteristics of coal and rock under the coupling of seepage and creep, four groups of tests of creep acoustic emission with different permeable water pressure and confining pressure were carried out. The results show that the cumulative seepage flow curve corresponds to the creep strain curve, which can be divided into three stages: initial stage, steady state stage and acceleration stage, and under the same confining pressure, the osmotic pressure increases with the interaction of seepage and creep. The larger the instantaneous strain of coal and rock, the higher the creep rate, the larger the seepage flow, the more active acoustic emission, the smaller the instantaneous strain of coal and rock, the lower the creep rate and the smaller the seepage, the larger the confining pressure is, the less the seepage is. During the whole process of percolation and creep, the acoustic emission is U shaped, and during the transition period from volume compression to volume expansion, acoustic emission is very active. The damage based on the Weibull distribution function shows that there is a damage threshold for each confining pressure, and when the damage exceeds this value, the coal and rock enter the stage of accelerated creep deformation. The damage threshold increased with the increase of confining pressure.
【作者单位】：西昌学院工程技术学院;
【分类号】：TD315

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