基于声发射检测CSG材料损伤演变及裂纹识别

为了从细观角度揭示胶凝砂砾石（CSG）材料损伤演变机制和裂纹的分类演化规律，结合声发射测试技术，采用Geiger时差定位法、上升角-平均频率法和高斯混合模型，对CSG材料的裂纹类型进行识别.结果表明：CSG材料的破坏过程可分为原始裂纹闭合、新生裂纹扩展、裂纹聚结和峰后破坏4个阶段；声发射事件的三维定位直观反映了裂纹萌生、扩展直至贯通的动态演化过程；通过裂纹类型识别，加载前期试件以剪切裂纹为主，后期拉伸裂纹占比增加，在临近破坏前，高水胶比时剪切裂纹与拉伸裂纹比约为2∶1，低水胶比时约为1∶1.

Damage Evolution and Crack Identification of CSG Material Based on Acoustic Emission Detection Technology

To reveal the damage evolution mechanism and crack classification evolution law of cemented sand and gravel （CSG） materials from a microscopic perspective， the Geiger time difference positioning method， rising angle-average frequency method， and Gaussian mixture model were employed to identify the crack types of CSG materials. The results show that the failure process of CSG materials can be divided into four stages， initial crack closure， new crack propagation， crack coalescence and peak failure. The three-dimensional positioning of acoustic emission events intuitively reflects the dynamic evolution process from crack initiation， propagation to penetration. Through crack type identification， shear cracks predominate in the early loading stage， and the proportion of tensile cracks increases later. Before failure， the ratio of shear to tensile crack is about 2∶1 at high water-binder ratio， and about 1∶1 at low water-binder ratio.