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Using Water Injection to Prevent Shaft Failure in the Jining No. 3 Coal Mine, China

  • Yanchun Xu
  • Mingze Du
  • Yaqi Luo
Technical Article
  • 25 Downloads

Abstract

Water injection into aquifers is a new approach for preventing shaft failure by stabilizing water levels. A series of injection tests was performed in the Jining no. 3 coal mine. Injection flow rates decreased over time as the water injection channels were blocked. Groundwater elevations in four observation boreholes and strain variations in the alluvial strata and shaft walls were analyzed to assess the effect of water injection on shaft failure and determine a preventive injection rate. The groundwater elevations in the observation boreholes decreased and the compressive strains in the alluvial strata and shaft wall increased overall over time. Although the water injection effect has weakened in recent years, it has still effectively slowed the increase of compressive strain in the shaft wall compared with conditions before water injection. We determined that the total and average injection rates for the four boreholes need to be approximately 20 m3/h and ≥ 5 m3/h, respectively, to maintain groundwater elevations and stabilize strain in the shafts. Measures such as oscillating pressurized water injection or increasing the number of injection boreholes could be used to increase injection flow rates and prevent shaft failure.

Keywords

Mining engineering Formation compression Additional stress Aquifer replenishment 

Nutzung von Wasserinjektionen zur Verhinderung von Schachtversagen im Kohlebergwerk Jining Nr. 3, China

Zusammenfassung

Wasserinjektion in Grundwasserleiter zur Stabilisierung des Wasserspiegels ist ein neuer Ansatz, um Schachtversagen zu verhindern. Im Kohlebergwerk Jining Nr. 3 wurde eine Reihe von Injektionstests durchgeführt. Die Injektionsraten gingen durch Verstopfung der Injektionskanäle mit der Zeit zurück. Der Grundwasserspiegel und die Veränderungen der Spannung in den alluvialen Schichten und in den Schachtwandungen wurden analysiert, um den Effekt der Wasserinjektion auf das Schachtversagen zu bewerten und die erforderliche Injektionsrate zu bestimmen. Insgesamt sank der Grundwassertand in den Beobachtungsbohrungen und stieg die kompressive Belastung in den alluvialen Schichten und der Schachtwandung. Obwohl der Effekt der Wasserinjektion in den vergangenen Jahren nachließ, hat er dennoch das Anwachsen der kompressiven Belastung in der Schachtwandung im Vergleich zu den Bedingungen vor der Wasserinjektion effektiv verlangsamt. Wir stellten fest, dass die Gesamtinjektionsrate für die vier Bohrungen etwa 20 m3/h sein muss und die mittlere Injektionsrate pro Bohrloch ≥ 5 m3/h, um die Grundwasserstände zu halten und die Belastung der Schächte zu stabilisieren. Maßnahmen wie oszillierende Druckwasserinjektionen oder die Erhöhung der Anzahl der Bohrlöcher könnten benutzt werden, um die Injektionsrate zu erhöhen und Schachtversagen zu verhindern.

Uso de inyección de agua para prevenir la falla de pozo en la mina de carbón No. 3 de Jining, China

Resumen

La inyección de agua en los acuíferos es un nuevo enfoque para prevenir la falla de pozo al estabilizar los niveles de agua. Una serie de pruebas de inyección se realizó en la mina de carbón Jining no. 3. Los caudales de inyección disminuyeron con el tiempo al bloquearse los canales de inyección de agua. Se analizaron las elevaciones de agua subterránea en cuatro pozos de observación y variaciones de tensión en los estratos aluviales y las paredes del pozo para evaluar el efecto de la inyección de agua en la falla de pozo y determinar una tasa de inyección preventiva. Las elevaciones de las aguas subterráneas en los pozos de observación disminuyeron y las tensiones de compresión en los estratos aluviales y en la pared del pozo aumentaron en general con el tiempo. Aunque el efecto de la inyección de agua se ha debilitado en los últimos años, ha disminuido aún más el aumento de la tensión de compresión en la pared del eje en comparación con las condiciones antes de la inyección de agua. Determinamos que las tasas de inyección totales y promedio para los cuatro pozos de perforación deben ser de aproximadamente 20 m3/h y ≥ 5 m3/h, respectivamente, para mantener las elevaciones de las aguas subterráneas y estabilizar la tensión en los ejes. Se podrían utilizar medidas como la inyección de agua a presión oscilante o el aumento del número de perforaciones de inyección para aumentar los caudales de inyección y evitar la falla de pozo.

注水预防济宁三矿(中国)井筒破坏

摘要:

注水稳定含水层水位法是一种新兴的预防井筒破坏的方法, 该方法在济三煤矿进行了一系列的试验。随着注水通道被堵塞, 注水流量逐渐减小。为评价注水法预防井筒破坏的效果以及确定合理的注水流量, 分析了4个水位观测孔的水位和冲积地层、井壁应变的变化规律。随着时间的推移, 水位观测孔的水位逐渐降低, 冲积地层和井壁压应变不断增大。虽然近几年的注水效果有所减弱, 但与注水前相比, 注水仍然减缓了井壁压应变增加的速率。为维持地下水位和井壁应变稳定, 确定了4个钻孔的总注水流量和平均注水流量, 分别为20m3/h和5m3/h。提出了振荡加压注水和补打注水孔等防治措施来增大注水流量, 预防井筒破坏。

Notes

Acknowledgements

We gratefully acknowledge the financial support provided by the National Basic Research Program of China (973 Program, 2013CB227903) and the National Natural Science Foundation of China (U1361209).

Supplementary material

10230_2018_576_MOESM1_ESM.pdf (210 kb)
Section connection of Z5 borehole pipe (PDF 209 KB)
10230_2018_576_MOESM2_ESM.pdf (54 kb)
Supplementary material 2 (PDF 54 KB)

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Copyright information

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

Authors and Affiliations

  1. 1.School of Resources and Safety EngineeringChina University of Mining and TechnologyBeijingChina
  2. 2.Mine Safety Technology BranchChina Coal Research InstituteBeijingChina

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