巴西劈裂条件下似斑状花岗岩试样力学及声发射特征

新城金矿新主井计划建设深度1 527 m,为了探究该主井1 300 m左右似斑状粗粒花岗岩受拉破裂的力学特征,取新主井工勘孔似斑状花岗岩岩样,借助应变检测装置及声发射检测设备等对劈裂受载的似斑状花岗岩进行加载过程的实时监测。试验结果表明:①花岗岩试样的横向应变变形分3个阶段,且临近破裂前应变变化趋势表现出非稳定性运动特征;②随着加载进程的推进,声发射计数整体活动性逐渐增强,计数的变化随时间进程呈现出起伏上升的规律,并且逐渐由稀疏变得密集;③结合运动稳定性理论、振动能量分析及试验结果,得到一次破裂过程中平均每个声发射信号携带的能量出现峰值的现象可以作为似斑状花岗岩劈裂破坏加剧前兆之一。

Mechanical and Acoustic Emission Characteristics of Porphyritic Granite Samples under Brazilian Splitting Condition

The planned construction depth of the new main well in Xincheng Gold Mine is 1 527 m. In order to explore the mechanical characteristics of tensile fracture of porphyry-like coarse-grained granite about 1 300 m in the main well， the granite samples from the prospecting borehole are collected. The loading process of split-loaded porphyritic granite is monitored in real time by means of strain detection device and acoustic emission detection equipment. The experimental results are as follows: （1） the transverse strain deformation of granite samples is divided into three stages， and the strain change process approaching to fracture shows the characteristics of unstable motion. （2） with the advance of the loading process， the overall activity of the acoustic emission counting rate increases gradually， and the change of the counting rate shows the characteristics of fluctuation with the time process， and gradually changes from sparse to dense. （3） based on the theory of motion stability and the analysis of vibration energy， it is concluded that the abnormal high value of energy carried by each acoustic emission signal on average can be used as one of the precursors of granite splitting failure.