Analysis And Research On Static And Dynamic Stability Of Crankshaft Panel Dam In Hami Pumped Storage Power Station

In recent years,with the vigorous development of water conservancy and hydropower projects,pumped storage power stations have been rapidly developed due to their advantages of regulating electric peaks,green cleaning and environmental protection.Due to the special design and the adaptability to the terrain,the upper reservoir of the pumped storage power station is built on the top of the mountain.The dam site is relatively open,usually with complex and harsh geological conditions,and there are many excavation materials for dam construction.The concrete face rockfill dam is widely used in pumped storage power stations because of its characteristics of local materials,economical application,simple panel construction,strong deformation adaptability,good seismic and frost resistance.The mountainous high earthquakes and geological topographical conditions in the western part of China are complex.The deformation characteristics of the dam under the earthquake load,the structural damage of the panel,the tensile deformation of the joint,and the stability of the dam slope have been severely tested.In this paper,the static and dynamic analysis of the actual project of the crankshaft concrete slab rockfill dam of the upper reservoir of Xinjiang Hami Pumped Storage Power Station is carried out.The main conclusions of the paper are as follows:(1)Through the review of relevant literatures,the dynamic calculation method,acceleration response and ground motion input mechanism of the face rockfill dam are discussed.The basic principle and calculation flow of the dynamic seismic analysis of the concrete face rockfill dam are summarized.(2)The static calculation of the construction and storage process of the dam is carried out,and the force deformation law of the dam during the completion period and normal operation period is studied.The results show that:due to the lower elevation of the dam,under the static force The vertical maximum settlement rate of the dam is 0.24%,the maximum deflection of the panel is 6.5cm,and the tensile stress occurs at the bottom of the panel and the dam axis.The overall deformation between the vertical j oint and the surrounding j oint between the panels is small.The dam has reliable safety and stability during water;(3)Exploring the combination of the most unfavorable seismic waves affecting the seismic safety of the dam and the input angle of the most unfavorable seismic waves in the horizontal direction.The conclusion is that the horizontal input angle of the most unfavorable seismic wave of the dam is +60°(modeling original coordinates are rotated 60° clockwise as reference.)Only a single seismic wave combination method and input direction can not accurately and reasonably reflect the most adverse impact of seismic load on the dam,and the damage of the earthquake may be underestimated in a certain probability;(4)Under the most unfavorable conditions explored above,the dynamic characteristics of the rockfill dam are studied,and the regular characteristics of the acceleration response,dynamic displacement and panel joint deformation of the dam are analyzed.The conclusion is that the dam is In the case of a design earthquake(100%surpass probability of 2%(3 86.2 gal)),the maximum position of the maximum dynamic response of the dam occurs at the top of the dam.The dynamic response law is affected by the shape of the dam body of the crankshaft.The position of the dam crest near the turning point of the left and right bank of the dam is mostly on the right bank,and the "whiplash" effect is obvious.(5)Calculate the permanent settlement after the end of the earthquake.By analyzing the residual displacement law of the dam body,it is found that the dam shrinks into the dam after the earthquake.This deformation mode is beneficial to the stability of the dam slope.At the same time,the stability of the slope of the dam slope downstream of the dam and the ultimate seismic capacity of the dam are studied.The ultimate seismic capacity of the dam is determined to be 0.55g?0.60g.At the same time,it points out the important links and key issues in the seismic analysis for the more and more convex type crankshaft slab dams emerging in domestic pumped storage power stations,which provides a useful reference for the design of crankshaft slab rockfill dams.