不同侧帮高度空区顶板破坏声发射特性研究

Acoustic Emission Characteristics of Goaf Roof Destruction with Different Sidewall Heights

当地下空区采用充填处理时,由于充填很难接顶,最终仍会破坏地下空区顶板并导致地表沉陷。通过配制空区的相似模拟材料和制作不同侧帮高度的空区试件,在单轴压力试验机上运用纵向均匀加载的方式对空区顶板进行破坏,同时基于声发射技术了解空区顶板变形破坏过程。研究表明:不同侧帮高度的空区顶板从加载到完全破坏都分别经历了微裂纹压密阶段、弹塑性压缩阶段、塑形变形阶段、完全破坏阶段和破坏后阶段;空区模型侧帮高度越低,空区顶板达到破坏所需的应力峰值越大,所对应的纵向位移量越大,空区顶板越不容易被破坏;空区顶板受纵向加载作用时,最易破坏的部位为中心部位。

Due to none-tight contact with filling body, when underground goaf roof is filled, it will eventually destroy the underground goaf roof and cause surface subsidence. Similar simulation materials and test specimens with different sidewall heights of the goaf are prepared. The goaf roof is destroyed by longitudinal uniform loading on the uniaxial pressure testing machine. Deformation and destruction process of the goaf roof is understood based on acoustic emission technology. The research shows that the goaf roof with different sidewall heights has experienced micro-crack compaction stage, elastic-plastic compression stage, plastic deformation stage, complete destruction stage and post-destruction stage. The lower the sidewall height of the goaf model, the greater the stress peak required for the goaf roof to achieve destruction, the greater the corresponding longitudinal displacement, and the less likely the goaf roof is to be destroyed. When the goaf roof is subjected to longitudinal loading, the most vulnerable part is the central part.