ISSN 1000-3665 CN 11-2202/P

    抚顺西露天矿蓄水期涉水软岩边坡失稳机制分析

    Instability mechanism of water-wading soft rock slope during storage period in Fushun west open-pit mine

    • 摘要: 抚顺西露天矿历经百余年开采,已形成面积逾12 km2、最大深度超400 m的矿坑,在贡献区域发展同时,也伴随着矿山边坡变形失稳等地质安全问题。随着其停采后“蓄水成湖”治理构想的提出,为提升矿区后续地质灾害防控能力,以潜在涉水软岩边坡为例,通过详细地质调查、岩土试验与数值模拟技术相结合,探究了矿区蓄水期软岩边坡的失稳滑坡机制。研究结果表明:(1)矿坑蓄水对软岩边坡产生4方面影响,按作用程度依次是弱化软岩、静水压脚、浮托减重和渗透反压,其中弱化软岩是涉水边坡失稳的主因;(2)同等“填蓄”改造强度下,软岩边坡中段稳定性相对最低,如当矿坑先填土至−150 m后再蓄水至−50 m时,软岩边坡东西段基本稳定,中段却失稳发生泥页岩切层滑坡,潜在滑体规模约133.4万 m3,建议改造过程中重点关注中段边坡的岩体隔水防渗和坡脚加压。研究成果可为抚顺西露天矿及类似深挖露天矿的修复治理提供参考。

       

      Abstract: The Fushun west open pit mine, encompassing over 12 km2, with a maximum depth exceeding 400 m, has undergone more than a century of intensive mining. While the mine has significantly contributed to regional development, it has also led to serious geological safety concerns, particularly slope deformation and instability. Following mine closure, a strategy of “water storage into lakes” for the treatment of the mine pit has been proposed. To prevent the occurrence of subsequent geological disaster events, this study investigated the mechanism of unstable landslide of soft rock slope during storage period in mining area through detailed geological survey, geotechnical test, and numerical simulation techniques. The results shows that pit water storage has four effects on soft rock slope: soft rock weakening, hydrostatic pressure on the toe of slope, floating weight reduction, and seepage force in slope according to influence degree. Soft rock weakening is the main cause of instability of water-wading slope. Under the same intensity of “filling and storage” transformation, the stability of the middle section of the soft rock slope is the lowest. For instance, when the pit is filled to −150 m and then water is stored to −50 m, the east and west sections of the soft rock slope are basically stable, while the middle section is unstable and prone to cutting through mudstone and shale to cause landslides. The potential sliding mass is about 133.4×104 m3. It is suggested that during the reconstruction process, special attention should be paid to water-proofing and seepage prevention measures for the rock mass, as well as reinforcing measures at the slope toe in the middle section of the slope. This study provide technical guidance for the repair and treatment of Fushun West open-pit mine and similar deep open-pit mines.

       

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