某抽水蓄能电站堆渣场危险性预测分析

Risk Prediction of Slag Dump in a Pumped Storage Power Station

山区水利工程、交通工程建设等往往产生大量的弃渣堆积体,其稳定性对生态环境和工程设施的安全运行至关重要。因此,弃渣场的稳定性评价和失稳后的危险性预测对于弃渣场位置选择和设计具有重要意义。某抽水蓄能电站最大的弃渣场位于天然冲沟上游沟脑,容积约700×10^(4) m^(3),最大高度240 m,冲沟中、下游右岸拟建地面开关站、地面通风洞出口、地面排风平台等设施。为了评价弃渣场失稳后对沟内建筑物的影响,首先基于弃渣场及冲沟工程地质条件评价了弃渣场稳定性,然后采用三维离散元颗粒流软件(particle flow code, PFC)研究了弃渣场失稳后的动力过程及其对沟内设施的危害性。结果表明:虽然渣场在天然状态下处于稳定状态,但在持续强降雨作用下仍可能发生失稳滑动,堆渣体失稳后将向冲沟下游运动,并与岸坡发生2次强烈碰撞,最终堆积在冲沟内,通风洞出口、地面排风平台将会受到冲击并被掩埋。由此可见,上述分析将为渣场及沟内设施的设计提供科学指导,并为同类工程危险性预测提供一种可以借鉴的方法。

Water conservancy projects and traffic engineering construction in mountainous areas often produce a large number of waste slag deposits,whose stability is crucial to the ecological environment and the safe operation of engineering facilities.For this reason,engineering assessment on stability and dynamic analysis after failure are important for the selection and design of landfills.The largest spoil ground of a pumped storage power station is located in the gully head upstream of the natural gully,with a volume of about 7 million m3,the maximum height is 240 m,and the ground switch station,ground ventilation tunnel outlet,ground exhaust platform and other facilities are proposed on the middle and downstream right banks of the gully.In order to evaluate the impact of the instability of the waste dump on the buildings in the ditch,firstly,the stability of the waste dump was evaluated based on the engineering geological conditions of the waste dump and the gully,and then the dynamic process of the instability of the waste dump and its harm to the facilities in the ditch were studied by using three-dimensional discrete element software particle flow code(PFC).The results show that although the slag yard is in a stable state under natural conditions,instability and sliding may still occur under the action of continuous heavy rainfall.After the instability of the slag heap,it will move downstream of the gully and collide strongly with the bank slope twice.Finally,it will accumulate in the gully,and the outlet of the ventilation tunnel and the ground exhaust platform will be impacted and buried.It can be seen that the above analysis will provide scientific guidance for the design of slag yard and facilities in the ditch,and provide a reference method for the risk prediction of similar projects.