为有效提取含有宏观构造煤体失稳破坏的前兆信息,采用试验方法开展了完整煤样和预制不同倾角大尺度单裂纹煤样单轴压缩过程破坏特征及电荷信号规律的研究。结果表明:随预制裂纹倾角(裂纹与轴线方向的夹角)减小,煤样的峰值应力逐渐降低,达到峰值应力时间逐渐缩短,煤样由拉伸劈裂破坏向剪切滑移破坏转变,同时新生翼裂纹由垂直预制裂纹面的翼裂纹向平行预制裂纹面的翼裂纹转变;预制裂纹煤样由于宏观裂纹的存在,更容易发生破裂,在应力峰前就有显著电荷信号产生,因此预制裂纹煤样破裂前兆信息比完整煤样更容易被捕捉;随预制裂纹倾角由60°→45°→30°减小,煤样破裂首次高值电荷信号出现的时间逐渐提前,分别为68.5%σ_c和65.5%T,60.5%σ_c和47.0%T,37.5%σc和30.0%T(T为煤样全程破坏时间),应力峰后破坏阶段电荷信号幅值逐渐减小,电荷累积量曲线突变点增多且首次突变点有所提前;预制裂纹的存在通过改变煤样的变形破裂过程及形式从而实现对煤样破裂产生电荷规律的影响;可根据预制裂纹煤样破裂电荷信号相关特征,对现场进行宏观地质构造探测、以及对煤岩体节理或断层的产状进行合理的推断。有望为预测预报煤岩动力灾害提供新的方法和途径。

In order to effectively extract the precursor information of containing macroscopic structural coal body in de- stabilizing failure,the authors have carried out the experimental research on the failure characteristics and charge sig- nal law of intact coal samples and coal samples with a prefabricated large different-dip crack under uniaxial compres- sion. The results show that with the decrease of pre-crack angle(the angle between the crack and the axial direction), the peak stress of coal samples decreases gradually,and the time reaching the peak stress de-creases,and the coal samples change from the tensile splitting failure to shear slip failure. At the same time,the new wing cracks are trans- formed from the wing cracks of the vertical pre-crack surface to the wing cracks of the parallel pre-crack surface. The pre-crack coal samples are more prone to rupture due to the existence of macroscopic cracks,and there are significant charge signals before the stress peak. Therefore,the precursory information of pre-crack coal samples is more easily captured than that of intact coal samples. With the pre-crack angle changing from 60° to 45° to 30°,the time of the first high-value charge signal in coal samples cracking process appears gradually advances,respectively 68. 5% σc and 65. 5% T,60. 5% σc and 47. 0% T,37. 5% σc and 30. 0% T(T for the whole destruction time of coal samples),and the amplitude of charge signal after the peak stress failure stage decreases gradually,as well as the mutation points in the charge accumulation curve increase and the first mutation point is advanced. The existence of pre-crack can affect the charge laws of coal samples by changing the deformation fracture process and the form of coal samples. Therefore, the charge signal related characteristics of pre-crack coal samples can be applied to detect the macroscopic geological structures and infer the occurrence of joints or faults of coal or rock mass reasonably. The study may provide new meth- ods and approaches for the prediction of coal and rock dynamic disasters.