基于非稳定渗流分析的尾矿库坝体稳定性研究

在汛期,尾矿库水位经常发生骤升骤降,坝体浸润线也随之发生急剧变化,坝体处于非稳定渗流状态,对坝体抗滑稳定产生不利影响。根据尾矿库调洪演算确定汛期尾矿库水位变化情况,建立尾矿库渗流稳定分析模型,以调洪演算确定的库水位作为非稳定渗流分析参数,进行坝体非稳定渗流分析,结果表明:在库水位骤升过程中,坝体内浸润线前部随着库水位不断上升而上抬,形成反坡S形;在库水位骤降过程中,坝体内浸润线前部随着库水位不断下降而下降,形成弧线形,但由于库水位变化速度较快,加上坝体渗透性的影响,浸润线后部变化很缓慢,在坝体内无法形成稳定的浸润线。基于此,本文分析了坝体抗滑稳定性,结果表明:在库水位骤升过程中,坝体抗滑稳安全系数仅从1.474下降至1.465,对坝体抗滑稳定性影响不大,但是一旦在最高洪水位形成稳定浸润线,坝体抗滑稳定安全系数明显降低至1.357;在库水位骤降过程中,坝体抗滑稳定安全系数仅从1.357上升至1.367,对坝体抗滑稳定性影响不大,但是一旦在正常运行水位形成稳定浸润线,坝体抗滑稳定安全系数明显提升至1.474。

Study on the stability of tailing dam based on unsteady seepage analysis

During flood season, the water level of tailings reservoir often goes up and down abruptly, and the seepage line of tailing dam also changes accordingly, and the dam body is in the state of unstable seepage, which has an adverse effect on the anti-sliding stability of the dam body. According to flood regulating calculation of tailing reservoir, the change of water level of tailing reservoir in flood season is determined. The seepage stability analysis model of tailing reservoir is established, and the reservoir water level determined by flood regulating calculation is taken as the unstable seepage analysis parameter to carry out the unstable seepage analysis of dam body. The results show that during the sudden rise of reservoir water level, the front part of the seepage line rises with the continuous rise of reservoir water level, forming an inverted S-shape; during the sudden drop of reservoir water level, the front part of the infiltration line falls with the continuous drop of reservoir water level, forming an arc shape. Due to the rapid change of reservoir water level and the influence of dam permeability, the rear of the seepage line changes very slowly, not form a stable seepage line within the dam. On this basis, the anti-sliding stability of the dam body is analyzed. The results show that the safety coefficient of anti-sliding stability of the dam body decreases from 1.474 to 1.465 during the sudden rise of the reservoir water level, which has little influence on the stability of the dam body. However, once the stability seepage line is formed at the maximum flood level, the safety coefficient of anti-sliding stability of the dam body decreases to 1.357 obviously. The safety coefficient of anti-sliding stability of the dam body increases from 1.357 to 1.367 during the sudden drop of reservoir water level, which has little influence on the stability of the dam body. However, once the stable seepage line is formed at the normal running water level, the safety coefficient of anti-sliding stability of the dam body increases to 1.474 obviously.