煤系上覆地层移动变形钻孔多参数监测技术

Multi parameter monitoring technology of borehole for movement and deformation of overlying strata of coal measures

  • 摘要: 精准获取煤层采动上覆地层结构全程演化特征与破坏规律是煤炭资源绿色、安全、高效开 采的重要研究内容。 光纤传感测试作为一种无源、高信噪比、高精度且长距离的变形监测技术,目 前在矿井工程领域得到应用。 结合煤系上覆地层移动变形研究现状及其技术发展思考,提出了钻 孔全断面多场多参数监测技术体系。 通过对光纤传感测试技术体系及常见的几类光纤技术(FBG,OTDR,BOTDR,BOTDA 和 BOFDA)在矿井应变监测中的应用分析,讨论了光纤监测技术在应用中 存在的 4 类关键技术问题;在对感知系统、调制解调系统、信号传输系统、数据处理与分析系统、远 程监控与预警处理系统 5 个系统组成研究的基础上,逐步构建了钻孔全断面多场多参量监测技术 体系,包括传感单元安装工艺、钻孔回填材料选取、多场参数联合反演及灾害预警等关键技术内容, 通过利用井下及地面钻孔布设岩土层变形等参数感知系统,进行多场多参数实时获取,可以实现对 岩土层变形破坏的动态预测评价。 结合陕西招贤井田一采区某工作面的地表垂直钻孔监测实例, 讨论了硬质顶板岩层钻孔全断面多场多参数监测的过程,揭示了岩层变形多场响应特征及其破坏 结构参数。 基于应变场和地电场(电阻率、电流)分布特征,并结合煤系地层地质资料,对煤层采动 期间超前支承压力、滞后垮落距离、“ 两带” 发育规律及离层演化特征等进行了综合分析。

     

    Abstract: It is an important research content of green,safe and efficient mining of coal resources to accurately obtain the whole process evolution characteristics and failure laws of the overlying strata structure of coal mining. As a passive,high SNR,high precision and long distance deformation monitoring technology,optical fiber sensing test has been applied in the field of mine engineering. Combined with the research status of the movement and deformation of the overlying strata in coal measures and the thinking of its technical development,a multifield and multiparameter monitoring technology system for the full section of borehole is putted forward. Through the analysis of the application of optical fiber sensor testing technology system and several common optical fiber technologies (Fiber braggart grating,FBG,Optical timedomain reflectometer Optical timedomain reflectometer,OTDR,Brillouin optical timedomain reflectometer,BOTDR,Brillouin optical timedomain analysis,BOTDA and Brillouin optical frequency domain analysis,BOFDA) in mine strain monitoring,four kinds of key technical problems existing in the application of optical fiber monitoring technology are discussed. Based on the research of five systems,including sensing system,modulation and demodulation system,signal transmission system,data processing and analysis system,remote monitoring and early warning processing system,a multi field and multi parameter monitoring technology system for the full section of borehole is gradually constructed,including the installation process of sensing unit,selection of borehole backfill materials,joint inversion of multi field parameters and disaster early warning. The dynamic prediction and evaluation of the deformation and failure of rock and soil layer can be realized by using the parameter sensing system of rock and soil layer deformation arranged in underground and surface boreholes to obtain multiple fields and parameters in real time. Combined with the surface vertical borehole monitoring example of a working face in first mining area of Zhaoxian Mine field,Shaanxi Province,the process of full section multifield and multiparameter monitoring of hard roof borehole is studied and discussed,and the multifield response characteristics of rock deformation and its failure structure parameters are revealed. Based on the distribution characteristics of strain field and geoelectric field (resistivity,current) and combined with the geological data of coal measure strata,the advanced abutment pressure,lagging collapse distance,the development law of “two zones” and the evolution characteristics of abscission layer during coal mining are comprehensively analyzed.

     

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