剧烈干湿交替下高海拔排土场安全稳定性研究

Study on safety and stability of high altitude dumps under intense drying-wetting alternation

为揭示剧烈干湿交替对高海拔排土场安全稳定性的影响,针对高海拔矿区水泥用石灰岩矿露采1、2号排土场,基于非饱和-饱和渗流理论,导入非饱和土基质吸力分布规律方程、抗剪强度方程,通过数值计算研究剧烈干湿交替下非饱和-饱和渗流场的演化特征及排土场稳定性情况。结果表明:随干湿交替强度加剧,排土场边坡表面土体由非饱和状态向饱和状态转变,土体抗剪强度降低;1号排土场未产生滑移,而2号排土场受干湿交替影响产生滑移,滑移区域位于坡脚至第2台阶,随干湿交替强度加剧向深层发展;排土场边坡位移随干湿交替强度增强不断增大;安全系数随干湿交替程度增强而减少。

In order to reveal impacts of intense drying-wetting alternation on safety and stability of high altitude dumps, numerical calculation was carried out for open mining No. 1 and No. 2 dump of limestone mine for cement in high altitude mining area. The distribution law equation of matric suction and shear strength equation were introduced for unsaturated soil based on unsaturated-saturated seepage theory. Therefore, the evolution characteristics of the unsaturated-saturated seepage field and stability of dumps were studied under intense drying-wetting alternation. The results show that as drying-wetting alternation intensity increases, the soil changes from unsaturated state to saturated one on dumps’ slopes, and its shear strength decreases. There is no slippage on slope of No. 1 dump. However, the No. 2 dump is affected by intense alternation, and slip area is located between slope foot and the second step, which develops into deep layer as the alternation intensity grows. The slope displacement of dumps increases continuously while safety factor decreases along with the increase of the intensity.