ISSN 1003-8035 CN 11-2852/P
    刘兵,郑坤,王超林,等. 冻融环境下基于声发射的层理砂岩劣化机理分析[J]. 中国地质灾害与防治学报,2024,35(1): 1-11. DOI: 10.16031/j.cnki.issn.1003-8035.202302008
    引用本文: 刘兵,郑坤,王超林,等. 冻融环境下基于声发射的层理砂岩劣化机理分析[J]. 中国地质灾害与防治学报,2024,35(1): 1-11. DOI: 10.16031/j.cnki.issn.1003-8035.202302008
    LIU Bing,ZHENG Kun,WANG Chaolin,et al. Mechanism analysis on layered sandstone degradation in freeze-thaw environment based on acoustic emission[J]. The Chinese Journal of Geological Hazard and Control,2024,35(1): 1-11. DOI: 10.16031/j.cnki.issn.1003-8035.202302008
    Citation: LIU Bing,ZHENG Kun,WANG Chaolin,et al. Mechanism analysis on layered sandstone degradation in freeze-thaw environment based on acoustic emission[J]. The Chinese Journal of Geological Hazard and Control,2024,35(1): 1-11. DOI: 10.16031/j.cnki.issn.1003-8035.202302008

    冻融环境下基于声发射的层理砂岩劣化机理分析

    Mechanism analysis on layered sandstone degradation in freeze-thaw environment based on acoustic emission

    • 摘要: 在冻融环境下,层理岩石的破裂对寒区工程稳定性存在一定的威胁,容易发生工程事故。将平行、垂直层理砂岩在0、20、40、60次冻融循环处理后,进行了单轴压缩和声发射试验,研究了不同层理砂岩的力学性质和岩石变形破坏过程中声发射特征参数的变化情况。结果表明:随着冻融作用的加强,两组试样的纵波速度都逐渐变小,孔隙率逐渐变大;平行组试样的抗压强度下降比例和应变增大比例都大于垂直组试样,说明平行组试样的劣化程度高于垂直组试样;两组不同层理砂岩在冻融循环作用下的声发射振铃计数演化曲线趋势变化一致,可分为三个阶段:平静阶段、阶梯式增长阶段、骤增阶段。不同层理方向的砂岩单轴破坏模式不同。平行组试样声发射b值变化呈倒“V”型,而垂直组试样声发射b值变化呈正“V”型,基于RA-AF值变化特征表明平行层理黄砂岩基本以拉伸破坏为主,而垂直层理砂岩在未处理时以拉伸破坏和剪切破坏为主,在60次冻融循环处理后,也以拉伸破坏为主。研究成果为寒区岩土工程的安全评估提供科学依据。

       

      Abstract: In the freeze-thaw environments, the fracturing of bedding rock poses a significant threat to the stability of the projects in cold regions, leading to potential engineering accidents. In this paper, uniaxial compression and acoustic emission tests were carried out on parallel and vertical stratified sandstones after 0, 20, 40, and 60 freeze-thaw cycles. The mechanical properties of different stratified sandstones and the changes in acoustic emission characteristic parameters during rock deformation and failure were studied. The results show that with the intensification of freeze-thaw effects, both longitudinal wave velocities of the two sample groups gradually decrease, and the porosity increases gradually. The proportion of compressive strength decrease and strain increase of the parallel group of samples is greater than that of the vertical group, indicating a higher level of degradation in parallel group. The trend of acoustic emission ringing count evolution curve of the two groups of different stratified sandstones under freeze-thaw cycles is consistent and can be divided into three stages: a calm stage, a stepwise growth stage, and a sudden growth stage. Uniaxial failure modes of sandstones with different bedding directions are different. The change in acoustic emission b-values for parallel group samples presents an inverted “V” shape, while for vertical group samples, it shows a normal "V" shape. Based on the various characteristics of RA-AF values, it is suggested that the parallel stratified yellow sandstone primarily undergoes tensile failure, while the vertical stratified sandstone is mainly dominated by both tensile and shear failures in the untreated condition, and also mainly dominated by tensile failure after 60 freeze-thaw cycles. The research results provide a scientific basis for the safety assessment of geotechnical engineering in cold regions.

       

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