基于随钻数据的岩体强度预测模型及其适配性评价

Research on rock mass strength prediction model and its suitability evaluation based on drilling data

  • 摘要: 为了研究在锚杆钻机钻进过程中实时识别顶板岩层强度及结构状态,为巷道掘进过程中进行顶板隐患探测提供技术途径,采用综合研究手段,揭示了不同强度岩体及组合岩体的钻进信号响应规律,研究了基于钻进数据的岩体强度表征及预测模型,并对比评估了其适配性。结果表明:推力、扭矩及转速等信号对围岩强度的变化具有较强的响应性,与岩层结构变化呈现一致性,三轴振动对岩体强度的响应性较不明显,但在岩层界面处信号突变显著;各表征参量及其强度表征值趋势与钻进信号趋势基本保持一致,基于钻头单位体积研磨能的单轴抗压强度表征模型与真实值偏离度最小(适配性最优);推力及扭矩与除三轴振动之外的其他参量均呈现较为明显的线性正相关关系,转速也同样具有较为明显的线性相关关系,但与除可钻性指数外其他特征均呈负相关趋势,三轴振动中,X方向与Y方向振动与其余各特征相关性程度较小,但仍存在一定相关性,其中Z方向振动中相关性程度极小。Attention-CNN模型在鲁棒性、准确率和适配性上表现最优,预测值与由单轴压缩实验所得的真实值之间决定系数R2达0.94,拟合度最高,在岩体单轴抗压强度预测上预测精度较其他模型的模型精度至少超出12%,研究成果为巷道顶板岩层强度实时感知及支护决策提供了理论与技术支撑。

     

    Abstract: In order to study the real-time identification of the strength and structural state of the roof strata during the drilling process of the anchor drilling rig, and to provide a technical way for the detection of roof hidden dangers in the process of roadway excavation, a comprehensive research method was used to reveal the drilling signal response law of different strength rock mass and combined rock mass. The rock mass strength characterization and prediction model based on drilling data was studied, and its suitability was compared and evaluated. The results show that the signals such as thrust, torque and rotational speed have strong responsiveness to the change of surrounding rock strength, which is consistent with the change of rock structure. The response of triaxial vibration to rock mass strength is not obvious, but the signal mutation at the rock interface is significant. The trend of each characterization parameter and its strength characterization value is basically consistent with the trend of drilling signal. The uniaxial compressive strength characterization model based on the unit volume grinding energy of the drill bit has the smallest deviation from the real value (optimal adaptability). The thrust and torque have obvious linear positive correlation with other parameters except the three-axis vibration, and the rotational speed also has obvious linear correlation, but it has a negative correlation trend with other characteristics except the drill-ability index. In the three-axis vibration, the X-direction and Y-direction vibration have little correlation with the other characteristics, but there is still a certain correlation, and the correlation in the Z-direction vibration is very small. The Attention-CNN model performs best in robustness, accuracy and adaptability. The coefficient of determination R2 between the predicted value and the real value obtained from the uniaxial compression test is 0.94, and the fitting degree is the highest. The prediction accuracy of the uniaxial compressive strength of rock mass is at least 12 % higher than that of other models. The research results provide theoretical and technical support for real-time perception and support decision-making of roadway roof rock strength.

     

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