注水法预防井筒破坏机理及其应用研究
Study on mechanism and application of water injection to prevent shaft failure
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摘要: 注水法是近年来新兴的预防井筒破坏的方法，是从控制含水层疏降的角度考虑，通过维持厚冲积层底部含水层水位稳定来预防井筒破坏。针对注水法预防井筒破坏机理认识不足、现场应用效果及可行性还需要系统的研究与探讨等问题，采用室内试验、数值模拟和现场实践等方法分析了黄淮地区深埋黏土的工程性质及失水变形机理，研究了疏、注水条件下井筒受力状态和地层变形情况，并对注水法的应用效果及可行性进行了探讨。结果表明：深埋黏土主要由伊利石、高岭石等膨胀性物质组成，且随埋深增大向半固态转变，松散冲积层底部含水砂层失水上覆土层变形以整体滑移为主；疏水条件下井壁垂直压应力持续增大，地层压缩量增大，注水后，井壁垂直压应力减小，地层压缩量减小甚至出现微抬升，注水有效抑制了附加应力的产生，缓解了井壁的受压状态。在此基础上，通过对济三煤矿注水法的应用效果以及朱仙庄煤矿大降深疏降条件下注水法应用的可行性分析，得出济三煤矿工业广场松散底部含水层可控性较强，现场多孔联合注水效果较好，有效预防了井筒破坏；朱仙庄煤矿地层注水的可控性较差，在大降深疏放的条件下，不适宜采用注水法进行预防井筒破坏。研究结果进一步揭示了注水法预防井筒破坏的机理，为同类井筒破坏防治提供理论基础与应用参考。Abstract: Water injection is an emerging method to prevent shaft failure in recent years. It is to prevent shaft failure by maintaining the stability of the water level at the bottom of the thick alluvium from the perspective of controlling aquifer dewatering. In view of the problems of insufficient understanding of the mechanism of water injection to prevent shaft failure, the field application effect and feasibility also require systematic research and discussion, the laboratory test, numerical simulation and field application were used to analyze the engineering properties and deformation mechanism of deep-buried clay under the condition of dewatering in Huang-huai region. The mechanism of water deformation was studied under the conditions of sparse and water injection and the deformation of the shaft. The effect and feasibility of water injection were also discussed. The results showed that the deep-buried clay is mainly composed of expansive materials such as illite and kaolinite, and it changes to a semi-solid state as the burial depth increases. The deformation of the overlying soil layer of the aquifer sand layer at the bottom of alluvium is mainly slippage.The stress on the shaft wall and the formation deformation under the condition of dewatering and water injection was studied. It was concluded that under the hydrophobic condition, the vertical compressive stress on the shaft wall continues to increase, and the formation compression increases. However, after water injection, the vertical compressive stress on the shaft wall decreases, and the formation compression decreases or even slightly lifts, indicating that water injection effectively suppresses the generation of additional stress and alleviates the stress state of the shaft wall. On this basis, through the application effect of the water injection method in the Jining No. 3 Coal Mine and the feasibility analysis of the application of the water injection method under the condition of large drawdown and drainage in the Zhuxianzhuang Coal Mine, it was concluded that the loose bottom aquifer in the industrial square in the Jinning No. 3 Coal Mine has strong controllability and the on-site porous joint water injection has a good effect and effectively prevents shaft destruction. The control of water injection in Zhuxianzhuang Coal Mine was poor, and under the conditions of large drawdown and drainage, it was not appropriate to use water injection method to prevent shaft failure. The research results further reveal the mechanism of water injection to prevent shaft failure, and provide a theoretical basis and application reference for the prevention and control of similar shaft failure.
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Keywords:
- vertical shaft /
- water injection method /
- thick alluvium /
- additional stress /
- stratum deformation
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