降雨条件下云南某铜矿露天边坡稳定性分析

Analysis on Stability of Opencast Slope of a Copper Mine in Yunnan Province under Rainfall Condition

边坡稳定性分析是关系到露天采场安全生产的核心问题,而大多数滑坡都是发生在雨季或降雨后的短时间内,因此在边坡稳定性分析中合理地考虑降雨作用的影响是十分必要的。以云南某铜矿露天采场为例,利用UDEC离散元软件,采用饱水状态下岩体物理力学参数,对处于降雨状态下的边坡稳定性进行了模拟分析。根据工程施工的实际情况,分别模拟了该边坡初始状态和5个开挖步骤共6个阶段的稳定性状态。结果表明:在降雨条件下,随着该边坡坡脚的开挖,坡体下部逐渐失去了支撑作用,安全系数降低至1以下时,上覆岩层便会沿着软弱夹层发生下滑;软弱夹层的强度是控制该段采场边坡稳定性的决定因素,降雨是边坡失稳的重要诱发因素;因此,后期生产要加强对软弱夹层的监测,必要时可进行工程处置,另外要做好边坡的排水工作。

Stability analysis of slope is the core issue for safe production of open pit mining. Most of landslides occur in rainy seasons or a short time after rainfall. So the effect of rainfall should be taken into consideration in the analysis of slope stability. The stability of the opencast slope of a copper mine in Yunnan Province was analyzed by the simulation of UDEC software based on the physico-mechanical parameters under water-saturated state. Based on the genuine condition of the engineering construction,the simulation analysis was divided into six steps including the original state of the slope and five excavation steps. The results show that the lower slope gradually lost support with the excavation in slope foot,and the overlying strata will slide along the weak intercalated layer when safety factor reduces to less than 1.The strength of the soft interlayer controls the stability of the stope slope,and rainfall is an important inducing factor of the slope instability. Therefore,the monitoring of the weak intercalations must be strengthened in later production,and conducted engineering treatment when necessary. In addition,it is also very important to deal with slope drainage appropriately.