砂岩在循环荷载作用下的Felicity效应研究

Felicity Effect of Sandstone under Cycling Loading Conditions

通过不同循环载荷水平作用下对砂岩变形特征的试验研究,探讨了砂岩在循环载荷作用下的状态参数、物性参数和声发射信息规律。试验结果表明:(1)砂岩在不同加、卸载阶段所产生的应变变化量不断增加,即随着加载水平的提高塑形变形加大;(2)砂岩在闭合阶段同样产生明显的声发射效应,而在卸载阶段未发现声发射现象;(3)砂岩在反复加、卸载过程中产生明显的Felicity效应;在每个应力水平下Felicity比不一样,应力水平越低,Felicity效应越明显,随着应力水平的增加,砂岩的各个物性和状态参数的Felicity效应有不断增大的趋势。

This paper presents the experimental study results of the state variables,physical parameters and acoustic emission properties of sandstone samples under various cyclic loading levels.The results indicate that,1）under loading-unloading conditions,the amount of plastic strain increases with the increase of loading level;2）distinct acoustic emissions are observed during the fissure closing period in the loading stage and no acoustic emissions are observed during the unloading stage;3）Distinct Felicity Effect is encountered in both loading and unloading conditions.Different Felicity Effects are found in different stress levels.A lower stress level usually contributes a higher Felicity Effect.With the increase of the stress level,the state variables and the physical parameters demonstrate a trend of increase.