王海,王晨光,张雁,等. 露天矿地下水控制技术及对边坡稳定性的影响[J]. 煤矿安全,2024,55(2):194−203. doi: 10.13347/j.cnki.mkaq.20222211
    引用本文: 王海,王晨光,张雁,等. 露天矿地下水控制技术及对边坡稳定性的影响[J]. 煤矿安全,2024,55(2):194−203. doi: 10.13347/j.cnki.mkaq.20222211
    WANG Hai, WANG Chenguang, ZHANG Yan, et al. Groundwater control technology in open pit mines and its impact on stability of end-slopes[J]. Safety in Coal Mines, 2024, 55(2): 194−203. doi: 10.13347/j.cnki.mkaq.20222211
    Citation: WANG Hai, WANG Chenguang, ZHANG Yan, et al. Groundwater control technology in open pit mines and its impact on stability of end-slopes[J]. Safety in Coal Mines, 2024, 55(2): 194−203. doi: 10.13347/j.cnki.mkaq.20222211

    露天矿地下水控制技术及对边坡稳定性的影响

    Groundwater control technology in open pit mines and its impact on stability of end-slopes

    • 摘要: 我国富水露天矿多且涌水量大,若矿山地下水或边坡处治不当,将面临着“水患难止、边坡难固、有矿难采”的窘境。为解决露天矿遇到的水患和边坡失稳的问题,基于我国露天矿先后发展的垂直疏水孔、水平疏水孔、坑下大口径疏水孔和井群疏水等抽排方式,坑底泄水巷、基坑降水和辐射井疏干等疏放方式以及钻孔注浆帷幕、地下混凝土连续墙帷幕、钻孔咬合桩帷幕、防渗膜帷幕等截水帷幕和地层回灌水帷幕等多种地下水控制技术;开展了不同露天矿地下水控制技术对地下水位、端帮边坡岩土体力学性质变化、坡体应力变化和边坡稳定性系数影响的研究,分析了截水帷幕作用下地下水位抬升与边坡稳定性变化规律。研究结果表明:通过抽排方式、疏放方式将露天矿山地下水疏干或疏降可有效降低地下水位,减少边坡岩土体含水率,提高边坡岩土体黏聚力和内摩擦角,减小坡体的静水压力和水平推力,整体提高边坡稳定性系数,但大量疏排地下水又造成水资源的浪费和污染;截水帷幕能够解决疏排降水造成的地下水位下降幅度太大、疏排水量巨大、水资源浪费和污染的问题;在截水帷幕作用下,露天矿截水帷幕外侧水位不断抬升,引起截水帷幕外侧边坡岩土体含水率增加、黏聚力和内摩擦角减小、坡体的静水压力和水平推力增大,而截水帷幕内侧边坡岩土体含水率减小、黏聚力和内摩擦角增大、坡体的静水压力和水平推力减小,从而引起露天矿边坡稳定性系数略有降低;通过截水帷幕可以控制露天矿边坡地下水位,进而保持边坡岩土体力学参数在合理范围,维持边坡稳定性系数在安全区间,实现露天矿地下水资源保护与边坡安全的平衡。

       

      Abstract: There are many rich water open-pit mines in China and the water inflow is large, if the mine groundwater or slope is not properly treated, it will face the dilemma of “water disaster, difficult strengthening of slope, and difficult mining of mines”. Open pit mines in China have developed a variety of groundwater control technologies such as vertical hydrophobic holes, horizontal hydrophobic holes, large diameter hydrophobic holes under the pit and well group hydrophobic and other pumping and draining methods, drainage alleys at the bottom of the pit, pit precipitation and radiation well draining, as well as water interception curtains and water curtains such as borehole slurry curtains, concrete diaphragm wall curtains, pile-row curtains and impermeable membrane curtains to solve the flooding and slope instability encountered in open pit mines. The effects of groundwater control techniques on groundwater level, changes in geotechnical properties of end-slope, changes in slope stress and slope stability coefficients in open pit mines were studied, and the effects of groundwater level lifting on slope stability under the action of water curtain were analyzed. The research results show that draining or de-watering the groundwater in the open pit can effectively reduce the depth of the groundwater, reduce the water content of the slope geotechnical body, improve the cohesion and internal friction angle of the slope geotechnical body, reduce the hydrostatic pressure and horizontal thrust of the slope body, and improve the overall stability coefficient of the slope; however, de-watering a large amount of groundwater can cause waste of water resources and pollution. The water cut-off curtain can solve the problems of too large a drop in groundwater level, huge volume of water drainage, waste of water resources and pollution caused by water drainage and precipitation. Under the action of water interception curtain, the water level on the outside of water interception curtain in the open pit mine keeps rising, which causes the water content of geotechnical body on the outside of water interception curtain to increase, the cohesion and internal friction angle to decrease, and the hydrostatic pressure and horizontal thrust of slope body to increase; while the water content of geotechnical body on the inside of water interception curtain decreases, the cohesion and internal friction angle to increase, and the hydrostatic pressure and horizontal thrust of slope body to decrease, which causes the stability coefficient of slope in open pit coal mine to slightly decreased. The slope stability coefficient is still within the safe range, and it also protects the groundwater resources of the open pit mine.

       

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