基于PFC3D的尾矿库地震稳定性模拟与分析

Simulation and analysis of the earthquake stability of the tailing reservoir based on PFC3D

以西辛庄尾矿库为例,研究了不同地震加速度情况下尾矿库内部结构的变形和稳定性。采用PFC3D对基岩、初期坝、尾黏土、尾粉土、尾粉砂部分进行模拟,对表现为连续体的基岩颗粒采用接触连接和平行连接,对表现为松散体的其余4部分主要采用接触连接。在地震动峰值加速度分别为0.1g、0.2g、0.4g、0.6g的震动波作用下,模拟了20 s内尾矿库内颗粒运动变形及边坡滑落情况。结果表明:随着震动的持续,颗粒位移从尾矿库坡底向坡顶发展;除初期坝外,尾矿库发生位移的颗粒都集中在初期坝产生被动土压力的区域(下滑区);尾矿库的破坏过程为从初期坝背侧尾粉砂部分发生位移,到初期坝破坏,再到尾粉砂边坡的整体下滑,该过程是加速的,开始于出现尾矿库边坡凹陷,停止于下滑区完全破坏。

The paper is aimed to introduce a simulated research of the earthquake stability of the tailing reservoir based on PFC3D by taking Xixinzhuang tailing reservoir as a case study sample. The sim- ulated research has been done under the conditions of different veloci- ties of the earthquake acceleration intentionally to study the deforma- tion and instability of the internal structure of the tailing reservoir, with the shaking simulation going on to the bedrock, initial dam, clay, silt soil, and silt sand by the said software PFC3D. It is sup- posed that the contact-bond and parallel-bond were used for the bedrock particles because of their continuous performance characteris- tics, whereas for the other four parts, the contact-bond was mainly used. The motion and the deformation of the tailing particles and the slope sliding movement were simulated during a short period of 20 s, with the condition of the ground motion peak acceleration as 0.1 g, 0.2g, 0.4g, 0.6g, respectively. The results of our simulation demonstrate that the appearance of the first destructive displacement doesn＇t seem to be in the initial dam, but rather in the part of silt sand blocked by the initial dam when the earthquake was going on. While as the vibration was going on, the initial dam began to get col- lapsed, which was followed by the final collapse of the part of silt sand along with the entire slope spoiled totally. It shows that, what- ever the state may be in, the greatest displacement vector is surely fo- cused on sliding area, and the displacement of the particles in the railings is focused on the area with earth stress from the initial dam. Thus, it can be summarized that the destruction process of the railings would come firstly to the silt sand behind the initial dam, which is followed by the initial dam damage, and finally followed by the total silt sand slope slide. More accurately speaking, the initial dam tends to collapse, resulting in the displacement of the particles in the large scope of the initial dam dorsal, which tends to promote the earth stress on tile initial dam. Thus, the process of the entire destruction was supposed to be sped up, began in the tailing slope sag, ended in the slide area destroyed completely.