强降雨条件下孔隙气压作用的高台阶排土场渗流与稳定性

强降雨作用下排土场非饱和带中的孔隙气压力会阻碍散土体的雨水入渗，从而进一步影响排土场的安全稳定。然而传统分析方法往往将孔隙气压力视为大气压力而忽略其对排土场安全的影响。本文依托江西某矿山高台阶排土场工程，基于现场实验和调查结果，结合水平分层的排土场典型剖面，分析了传统方法与考虑孔隙气压力的高台阶排土场渗流规律及其安全稳定性，探讨了强降雨条件下孔隙气压对高台阶排土场湿润锋、孔隙水压力和边坡安全系数的影响。研究结果表明:降雨入渗初期的孔隙气压不显著，其对高台阶排土场稳定性不产生直接影响；但随着降雨的持续，孔隙气压作用开始显现，使得高台阶排土场的入渗速率降低，湿润锋下移速度变慢，孔隙水压上升变缓，强降雨对高台阶排土场稳定性的影响也出现一定延时；在降雨入渗中期，孔隙气压将保持恒定，延时效应会随入渗深度的增加而增强；在降雨入渗后期，当湿润锋下移至分层临界面时，孔隙气压平衡被破坏，将继续增大直至新的恒定值，对高台阶排土场的影响加剧；在湿润锋下移至相同深度时，孔隙气压作用下的高台阶排土场安全系数明显降低。研究成果将为强降雨条件下的高台阶排土场的长期安全运行和灾害监测预警提供理论依据。 

Seepage and stability analysis of pore air pressure on a high-bench dump under heavy rainfall

Under heavy rainfall, the pore air pressure in the unsaturated zone of a dump hinders rainwater infiltration in loose soil, which further affects the safety and stability of the dump. However, traditional analysis methods often regard pore air pressure as atmospheric pressure and ignore its impact on dump safety. Relying on the high bench dump project of a copper mine in Jiangxi, basing on the field test and survey results and combing with the horizontal slice of a typical dump profile, the seepage law and safety stability of a high bench dump with traditional methods while considering the pore air pressure were analyzed. Moreover, the influence of pore air pressure on a wet front, pore water pressure, and slope safety factors of high bench dump under heavy rainfall conditions were discussed. The research results show that pore air pressure at the initial stage of rainfall infiltration is not significant, and pore air pressure does not have a direct impact on the stability of the high bench dump. However, as the rainfall continues, the effect of the pore air pressure begins to appear, reducing the infiltration rate of the high bench dump. Further, the downward movement speed of the wetting front becomes slower, the pore water pressure rises slowly, and the influence of the heavy rainfall delays the stability of the high bench dump. In the middle of rainfall infiltration, the pore air pressure remains constant, the delay effect varies, and the penetration depth increases. In the late stage of rainfall infiltration, when the wetting front moves down to the critical plane of the layering, the pore air pressure balance is destroyed, continuing to increase to a new constant value, which increases the impact on the high bench dump. When the traditional method of wetting front and considering the pore air pressure of wetting front move down to the same depth, the safety factor of the high bench dump under the action of pore air pressure is obviously reduced. The research results provide a theoretical basis for long-term safe operation and disaster monitoring and early warning of high bench dump under heavy rainfall conditions.