不同含水率状态下黄土崩塌地质灾害声发射响应特征模型试验

Modeling of Acoustic Emission Response Characteristics of Loess Collapse Geohazards under Different Water Content Conditions

为有效解决黄土崩塌灾害孕灾周期短、隐蔽性强、前兆信息难以捕捉的问题,深入研究黄土崩塌监测新方法具有重要的工程与科学意义。目前声发射技术在岩质边坡的监测预警中已取得较好的应用,但将其应用于黄土崩塌监测尚缺乏可靠依据。为此,采用含水率分别为3%、7%、10%的单面连接型黄土崩塌模型开展试验,结合有源波导方式进行实时声发射监测,探索不同含水率下黄土崩塌过程中的声发射响应特征,分析黄土崩塌的破坏形式与变形破坏过程中声发射振铃计数的时序演化特征。结果表明:含水率为3%、10%的黄土崩塌破坏模式以小块黄土的局部崩落为主,7%的黄土崩塌破坏模式以大块黄土的整体崩塌为主。随着黄土崩塌变形破坏加剧,声发射振铃计数大小也随着增加,且在黄土崩塌破坏前,声发射振铃计数数值会快速上升,可将振铃计数开始“突增”作为黄土崩塌的破坏前兆信息。

In order too effectively mitigate losses induced by loess collapse which is normally characterized by suddenness,concealment,and difficulty in capturing precursor information,the investigation into new methods for monitoring of loess collapse holds great engineering and scientific significance.There still remains a lack of a reliable theoretical and/or practical basis for the application of acoustic emission technology in monitoring and early-warning of loess collapse,while this technique has been found successful rock slopes.The single side connected loess slope model tests with water contents of 3%,7%and 10%were conducted.The tests were complemented by employing active waveguide method for real-time acoustic emission monitoring in order to explore the acoustic emission response characteristics during the process of loess.The destructive form of loess collapse and the time-sequence evolution of acoustic emission counts in the deformation and destruction process were also analyzed.The results indicate that the failure pattern of loess slope model with 3%or 10%water content is dominated by local collapse of small pieces.On the other hand,the failure pattern of loess model with 7%water content is dominated by the overall collapse of large pieces.With deformation,the value of acoustic emission events also increased.As the acoustic emission counts increased rapidly before the overall failure,the initial point can be regarded as a precursor of loess collapse.