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Method to Predict the Height of the Water Conducting Fractured Zone Based on Bearing Structures in the Overlying Strata

  • Feng Wang
  • Jialin XuEmail author
  • Shaojie Chen
  • Mengzi Ren
Technical Article
  • 11 Downloads

Abstract

Numerous mining-induced water inrush hazards have been recorded in northern and eastern China, wherein landforms comprise thick unconsolidated layers. To prevent such hazards, the height of the water conducting fractured zone (WCFZ) must be determined in advance. This study presents a method to predict the height of this zone by determining the location of the key strata (KS) and considering the overburden load transfer under an arch structure in the unconsolidated layers. When the distance between the primary key stratum (PKS) and coal seam is more than 7–10 × M, where M refers to the mining height, the WCFZ tends to extend up to the floor level of the first KS, approximately the same distance (7–10 × M) above the mining seam, thereby making the height of this zone equal to the distance between the KS and coal seam. When the vertical distance between the PKS and coal seam is less than 7–10 × M, the height of this zone tends to be equal to or greater than the thickness of the bedrock strata. The theoretical results were verified by field observations.

Keywords

Water inrush Key strata Arch structure in unconsolidated layers Load reduction factor 

Zusammenfassung

In den nördlichen und östlichen Regionen Chinas sind zahlreiche bergbauinduzierte Wassereinbrüche im Zusammenhang mit der Verbreitung mächtiger, unkonsolidierter Schichten zu verzeichnen. Um solche Gefährdungen zu verhindern, muss die Mächtigkeit wasserführender Bruchzonen im Voraus bestimmt werden. In dieser Studie wird eine Methode zur Vorhersage von Mächtigkeiten wasserführender Bruchzonen vorgestellt, welche die Lage von sog. Schlüsseleinheiten (key strata KS) unter Berücksichtigung des Überlagerungsdrucks des Deckgebirges unterhalb von Gewölbestrukturen in unkonsolidierten Schichten einbezieht. Wenn der Abstand zwischen der primären Schlüsseleinheit (PKS) und dem Kohleflöz mehr als das 7–10-fache von M beträgt, wobei M die Mächtigkeit des Kohleflözes ist, erstreckt sich die wasserführende Bruchzone in der Regel bis zur Basis der ersten Schlüsseleinheit (KS), welche sich ungefähr im gleichen Abstand (7–10 mal M) über dem Abbaugebiet befindet. Somit entspricht die Mächtigkeit der wasserführenden Bruchzone dem Abstand zwischen KS und dem Kohleflöz. Wenn der vertikale Abstand zwischen der primären Schlüsseleinheit (PHS) und dem Kohleflöz weniger als das 7–10-fache von M beträgt, ist die Mächtigkeit der wasserführenden Bruchzone in der Regel gleich oder größer der Mächtigkeit der Festgesteinseinheit unterhalb von unkonsolidierten Gesteinen. Die theoretischen Ergebnisse werden durch Feldbeobachtungen aus China bestätigt.

Resumen

Se han registrado numerosos riesgos de irrupción de agua inducidos por la minería en las regiones norte y este de China, donde los accidentes geográficos incluyen gruesas capas no consolidadas. Para evitar estos riesgos, la altura de agua fluyendo por la zona de fractura debe determinarse de antemano. Este estudio presenta un método para predecir la altura de la zona de fractura que fluye del agua mediante la determinación de la ubicación de los estratos clave (KS) con la consideración de la ley de transferencia de la sobrecarga bajo la estructura del arco en los efectos de capas no consolidadas (ASUL). Cuando la distancia entre el estrato clave primario (PKS) y la capa de carbón es mayor que 7-10 veces M, donde M se refiere a la altura de extracción de carbón, el agua fluyendo por la zona de fractura tiende a extenderse hasta el nivel del piso del primer KS, ubicado aproximadamente la misma distancia (7–10 veces M) sobre la veta, haciendo que la altura de agua fluyendo por la zona de fractura sea igual a la distancia entre KS y la veta. Cuando la distancia vertical entre PKS y la capa de carbón es menor de 7 a 10 veces M, la altura de agua fluyendo por la zona de fractura tiende a ser igual o mayor que el espesor de los estratos de roca madre. Los resultados teóricos se verificaron mediante observaciones de campo realizadas en China.

抽象

基于覆岩承载结构的导水裂隙带高度预测方法 中国北部和东部的厚松散层地区已经发生过多次采矿引起的突水事故。为防止此类灾害,必须提前确定导水裂隙带高度。在考虑松散层拱结构(ASUL)荷载传递规律的基础上,确定关键层(KS)位置,提出了一种预测导水裂隙带高度的方法。 当主关键层(PKS)与煤层间距离大于7-10倍煤层采煤高度(M)时,导水裂隙带将向上发展至第一关键层(KS)底部,第一关键层也位于开采煤层上方约7-10倍采高的位置;此时,导水裂隙带高度等于关键层(KS)与煤层的间距。当主关键层(PKS)与煤层的垂直间距小于7-10倍采高(M)时,导水裂隙带高度将等于或大于基岩厚度。系列野外监测(中国)已经验证了该理论的可靠性。

Notes

Acknowledgments

This research was supported by the project supported by the National Natural Science Foundation of China (51904162), Shandong Provincial Natural Science Foundation, China (ZR2018BEE001), the Taishan Scholars Project, and the Scientific Research Foundation of SDUST for Recruited Talents (2017RCJJ006). We thank Editage [http://www.editage.cn] for English language editing. Thanks also to the anonymous reviewers for their constructive comments and suggestions.

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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  • Feng Wang
    • 1
    • 2
  • Jialin Xu
    • 3
    • 4
    Email author
  • Shaojie Chen
    • 1
    • 2
  • Mengzi Ren
    • 2
  1. 1.State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and the Ministry of Science and TechnologyShandong University of Science and TechnologyQingdaoChina
  2. 2.College of Mining and Safety EngineeringShandong University of Science and TechnologyQingdaoChina
  3. 3.State Key Laboratory of Coal Resources and Safe MiningChina University of Mining and TechnologyXuzhouChina
  4. 4.School of MinesChina University of Mining and TechnologyXuzhouChina

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