关键词: 节理砂岩, 干湿循环, 单轴压缩, 声发射监测, 声发射b值

Abstract: Dry-wet cycles cause irreversible cumulative damage to rocks,and the deformation and failure process of rock is accompanied by obvious acoustic characteristics.In order to explore the deformation and failure mechanism of jointed sandstone after dry-wet cycles,we monitored the acoustic data of damage and failure of jointed sandstone specimens under indoor uniaxial compression test by acoustic emission (AE),and further examined the evolution characteristics of acoustic emission parameters of intact single-jointed and double-jointed sandstone specimens in the deformation and failure process after different dry-wet cycles (0,1,5,10,15 and 20 cycles).Results elucidated that with the proceeding of dry-wet cycles,the post-peak plastic characteristics of sandstone rock specimens gradually increased,and the AE activities undergone weak,enhanced,steep increase,and intense stages;the duration of violent phase of acoustic emission,the decrease of cumulative ringing count,and the b value of AE in the process of deformation and failure gradually increased.The b values of AE of intact rock samples at any dry-wet cycle were larger than those of jointed rock specimens.The research findings offer reference for researching the deformation and failure mechanism of jointed rockmass under dry-wet cycles.

Key words: jointed sandstone, dry-wet cycles, uniaxial compression, acoustic emission monitoring, b value of acoustic emission