融合空间特征的孔间电阻率时序预测模型及应用

A time series forecasting model integrating spatial features for inter-borehole resistivity and its application

  • 摘要:
    背景 矿井电阻率法是煤矿水害监测的核心技术,然而传统方法受限于测点稀疏与空间分辨率不足,难以捕捉复杂地质条件下的动态电阻率变化。
    目的和方法 针对这一难题,提出一种融合时空特征的深度学习预测模型,构建了基于长短期记忆网络(LSTM)的孔间电阻率预测框架,通过皮尔森相关性分析筛选关键空间测点,实现对未知区域电阻率的高精度预测。首先通过空间相关性热力图量化测点间电性关联,确定最优邻近点数量为5个,有效降低数据冗余并提升模型泛化能力。模型架构结合LSTM门控机制捕捉电阻率时序依赖,同时融合多测点空间信息,解决了传统模型对长序列梯度消失的敏感性问题。以鄂尔多斯唐家会煤矿 61304工作面为工程背景,基于底板定向孔监测数据,对比分析LSTM与传统循环神经网络(RNN)的预测性能。
    结果和结论 LSTM 模型在平均绝对误差(EMA=0.058 2)、均方误差(EMS=0.005 2)和决定系数(R2=0.937 7)等指标上优于 RNN,且在 10% 噪声干扰下 R2 仅下降 0.02,验证了其鲁棒性。将LSTM模型应用于注浆过程早期、中期与后期的动态监测,通过对实测稀疏数据进行预测补全,获得了高密度的时空电阻率数据集。基于此高密度数据的反演成像结果证实,该方法能有效恢复低密度监测下被忽略的地质结构连续性,并成功识别出在低密度反演结果中无法显现的弱异常区域。本方法能够有效弥补传统监测的空间分辨率不足,为复杂地质条件下的水害动态监测与精准预警提供一种技术途径。

     

    Abstract:
    Background Mine resistivity prediction serves as a core technique for water hazards monitoring in coal mines. However, due to sparse monitoring points and insufficient spatial resolution, conventional prediction approaches fail to capture dynamic resistivity variations under complex geological conditions.
    Objective and Methods  To address this challenge, this study developed a deep learning-based time series forecasting model integrating spatial features for inter-borehole resistivity. Using a prediction framework constructed based on long short-term memory (LSTM) and critical spatial monitoring points selected through Pearson correlation analysis, this model (also referred to as the LSTM model) enabled high-precision prediction of resistivity in unknown areas. Specifically, the electrical connectivity between monitoring points was quantified using spatial correlation heatmaps. The optimal number of neighboring points was determined at five to reduce data redundancy and enhance the generalization capability of the LSTM model. The model architecture captured temporal dependencies in resistivity data using the gating mechanisms of LSTM and incorporated spatial information from multiple monitoring points, reducing the sensitivity of conventional models to vanishing gradients associated with long sequences. Against the engineering background of mining face 61304 in the Tangjiahui coal mine, Ordos City, this study compared the prediction performance of the LSTM model and the recurrent neural network (RNN) model based on the monitoring data from directional boreholes in the coal seam floor.
    Results and Conclusions The results indicate that the LSTM model outperformed the RNN model in terms of mean absolute error (EMA = 0.0582), root mean square error (EMS = 0.005 2), and coefficient of determination (R2 = 0.937 7). Under 10% noise interference, the R2 value of the LSTM model decreased by merely 0.02, demonstrating strong robustness. The LSTM model was applied to the dynamic monitoring during the early, middle, and late grouting stages. A high-density spatiotemporal resistivity dataset was obtained by supplementing sparse measured data with predicted data. The inversion imaging results based on this dataset confirm that the LSTM model can restore the continuity of geological structures that is ignored in low-density monitoring while successfully identifying weak anomaly areas that cannot be reflected in the inversion results derived using low-density data. The LSTM model can effectively overcome the limitations of low spatial resolutions in traditional monitoring, offering a robust technical approach for the dynamic monitoring and accurate early warning of water hazards under complex geological conditions.

     

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