受载煤体多参量随钻监测试验与随钻突出预测方法

Multi-parameter while-drilling monitoring experiment of loaded coal and while-drilling outburst prediction method

  • 摘要: 煤与瓦斯突出预测结果直接关系着煤层安全开采和防突措施科学实施,但现行以瓦斯参数为主的突出预测指标体系难以超前反映工作面前方煤体应力和物理力学性质变化。钻孔钻进过程蕴含着大量反映煤体突出危险性的信息,为深度挖掘钻进信息与煤体应力和物理力学性质的关系,自主研制了受载煤体模拟钻进与多参量随钻监测试验系统。该系统中,矿用液压回转钻机能够还原井下钻机钻进能力,三向独立加载和梯度加卸载模块能够还原井下煤体应力非均匀分布,4个300 mm×400 mm×400 mm的试验空间可以实现非均质煤体连续钻进,同时试验系统能够实现钻进参数和声发射信号的随钻采集。利用试验系统开展了不同煤体应力和物理力学性质条件下随钻监测试验,结果表明:随煤体应力增大,钻机转矩、推进力相应增大,转速相应减小;不同钻进参数对不同煤体物理力学性质响应敏感性不同,钻机转矩与煤体三轴抗压强度呈正相关关系,钻机转速与煤体单轴抗压强度呈负相关关系,钻机推进力与煤体内摩擦角呈正相关关系;不同物理力学性质煤体随钻声发射频带分布不同,峰值频率与单轴抗压强度、三轴抗压强度、内摩擦角呈负相关关系。进一步从理论分析与试验研究方面探讨了煤体应力、煤体物理力学性质、煤层瓦斯大小随钻评价可行性,并建立了煤与瓦斯突出危险随钻预测模型,讨论了煤与瓦斯突出随钻综合预测的可行性,研制了近钻头声振信号随钻采集装置,为推进煤与瓦斯突出随钻预测技术发展提供了一定的理论和技术支撑。

     

    Abstract: The prediction results of coal and gas outburst are directly related to the safe mining of coal seams and the scientific implementation of outburst prevention measures. However, it is difficult for the current outburst prediction index system to reflect in advance the changes in the stress and physical and mechanical properties of the coal in front of the working face. A large amount of information reflecting the outburst hazard of the coal is contained in the drilling process. In order to deeply explore the relationship between the drilling information and the stress and physical and mechanical properties of the coal, a simulation drilling and multi-parameter while-drilling monitoring test system for the loaded coal has been independently developed. In this system, The mine-used hydraulic rotary drilling rig can restore the drilling ability of the underground drilling rig. The three-way independent loading and one-way differential loading and unloading module can restore the non-uniform distribution of the stress of the underground coal. The four test spaces of 300 mm×400 mm×400 mm can realize the continuous drilling of the heterogeneous coal. At the same time, the test system can realize the while-drilling acquisition of the drilling parameters and the acoustic emission signal. Using this test system, the while-drilling monitoring experiments under different coal stress/physical and mechanical property conditions have been carried out. The results show that as the coal stress increases, the torque and the pushing force increase correspondingly, and the rotational speed decreases correspondingly. The response sensitivity of different drilling parameters to different physical and mechanical properties of the coal is different. The torque is positively correlated with the triaxial compressive strength of the coal, the rotational speed is negatively correlated with the uniaxial compressive strength of the coal, and the pushing force is positively correlated with the internal friction angle of the coal. The while-drilling acoustic emission frequency band distribution of coal bodies with different physical and mechanical properties is different, and the peak frequency is negatively correlated with the uniaxial compressive strength, the triaxial compressive strength, and the internal friction angle. The further theoretical analysis and experimental research explored the feasibility of evaluating coal stress, physical and mechanical properties of coal, and coal seam gas content with drilling, and a while-drilling multi-parameter prediction model for coal and gas outburst is established. The feasibility of the comprehensive while-drilling prediction research of coal and gas outburst is discussed, and a while-drilling acquisition device for the near-bit acoustic and vibration signals is developed, which provides a theoretical basis and equipment support for promoting the development of the while-drilling prediction technology of coal and gas outburst.

     

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