基于矩张量的含孔洞砂岩声发射特性模拟研究

    DEM simulation on AE characteristics of sandstone containing holes based on moment tensors

    • 摘要: 岩体中的充填物对岩土工程结构稳定性具有显著影响,使得含孔洞岩体结构失稳破坏出现不确定性。为了探究含孔洞岩体中孔洞被充填后其在受载时的声发射响应机制,采用离散元法和矩张量理论对不同充填条件下的含孔洞砂岩进行单轴压缩数值模拟,分析破坏过程中的声发射事件类型、幅值分布和b值特征。研究结果表明:①在充填条件b、c下,圆形、矩形和梯形试样的强度增长率分别为2.75%、7.12%、4.35%和8.30%、13.14%、18.03%。②充填物的存在使试样声发射更为剧烈,且剧烈程度与充填物强度正相关,充填试样的声发射累计数和声发射率均高于未充填试样。③在充填c条件下,剪切型声发射占比高于其他充填条件,声发射频数-幅值呈正态分布。④在相同充填条件下,圆形孔洞的声发射b值最大,其次为矩形孔洞和梯形孔洞; 在相同孔洞形状下,充填c条件下的b值最小,充填a条件下的b值最大。研究结果可为工程中不同充填条件下含孔洞岩体的声学破坏特征分析提供一定的参考。

       

      Abstract: The filling material within rock masses significantly affects the structural stability of geotechnical engineering projects, introducing uncertainty to the instability and failure processes of rock masses containing holes. To explore the acoustic emission (AE) response mechanism of sandstone containing holes with different filling materials under loading, the discrete element method (DEM) combined with moment tensor theory was employed to simulate uniaxial compression tests on such specimens. The types, amplitude distribution, and b-value characteristics of AE events during the failure process were systematically analyzed. The results indicate that: ① Under filling conditions b and c, the strength increase rates for specimens with circular, rectangular, and trapezoidal holes were 2.75%, 7.12%, and 4.35%, and 8.30%, 13.14%, and 18.03%, respectively.② The presence of filling material led to more intense AE activity, with the intensity positively correlated with the strength of the filling material. Both the cumulative number of AE events and the AE rate were higher for filled specimens compared to unfilled ones.③ Under filling condition c, the proportion of shear-type AE events was higher than that under other filling conditions, and the frequency-amplitude distribution of AE events followed a normal distribution.④ Under the same filling condition, the AE b-value was largest for the circular hole specimen, followed by the rectangular and trapezoidal hole specimens. For the same hole shape, the b-value was the smallest under filling condition c and the largest under filling condition a. These findings provide a valuable reference for analyzing the acoustic failure characteristics of rock masses containing holes under various filling conditions in engineering practice.

       

    /

    返回文章
    返回