【作者】 周伟；

【导师】 李守义；

【作者基本信息】 西安理工大学 ， 水工结构工程， 2008， 硕士

【摘要】 河床式水电站水头比较低,而单机流量通常较大,这样水电站厂房的进水口、蜗壳和尾水管等尺寸较大。厂房结构主要由上游挡水墩墙、流道、下游挡水墩墙、排沙孔、主厂房上部和下部结构等组成,是由多个孔洞组成的复杂三维孔洞结构。作为挡水建筑物,厂房上、下游面要承受水压力,使河床式水电站厂房的内力分布较其它型式的厂房更加复杂。进水口、闸墩、蜗壳、尾水管等主要部位都处于高应力状态,厂房坝段横缝止水的合理布置对缓解以上部位的应力状态非常有利。但到目前为止,对于河床式水电站厂房坝段横缝止水布置形式还没有统一的规定,国内外在此方面的研究很少,设计中主要是根据工程经验布置。因此,通过理论分析和数值计算分析,提出合理的布置形式是十分必要的。本文结合实际工程,本着“从工程中来,到工程中去”的原则,以河床式水电站厂房坝段横缝止水布置形式研究为主导,建立了不同止水布置形式的河床式水电站厂房模型,分别进行了三维有限元静力和动力计算,对比分析了几种常见的厂房坝段横缝止水布置形式下厂房主要结构应力分布规律,通过厂房坝段横缝止水布置形式对厂房主要结构应力的敏感性分析,提出了合理的止水布置形式,为工程设计提供参考依据,对节省工程投资具有重要意义。通过计算分析得出:合理的横缝止水布置能有效改善厂房坝段进水口、蜗壳、尾水管、尾水出口等部位的应力状态。在满足运行要求的前提下,厂房坝段横缝上游止水尽可能向下游移,下游止水尽可能向上游移,使进水口和尾水出口处内、外水压力接近平衡,减小正常运行情况下该部位的拉应力;水平止水应该适当抬高,使流道内、外水压力接近平衡,减小正常运行情况下蜗壳和尾水管的拉应力。另外,由于厂-厂坝段和厂-坝坝段两横缝内止水位置不同,充水面积不同,水压力不平衡,常常使厂房坝段整体受扭,导致进水口或出水口角缘应力很大,应当尽可能调整厂房坝段两侧横缝内的止水布置,减小两侧的不平衡水压力,能有效改善以上部位的应力状态;对于单机流量较大的水电站厂房,横缝止水布置不能单纯从静力角度去考虑,还应进行动力校核计算,通过综合分析,选择满足各种运行工况的最佳横缝止水布置。更多还原

【Abstract】 In general, the head pressure of power station in river channel is lower comparatively, but the unit discharge is always greater, in this way, the dimension of the hydropower house is usually larger. The mill construction is composed of retaining wall in upstream, flow passage, retaining wall in downstream, sand sluice, superstructure and substructure of main generator room, which is a 3D cavity structure. As water retaining structure, the upstream face and downstream face are direct-contacted with water, formed a heavenward face, bearing horizontal applied force of upstream and downstream, lead to the distribution of inner force is more complex than other type power house. The main parts of mill construction all are in high stress state such as pier, spiral case, draft tube etc. Reasonable water seal layout is beneficial for releasing stress state of those parts. Until the present time, there is no uniform regulation about water seal layout of power station in river channel. There is no report and study about this aspect, both here and abroad. The lay lout always based on engineering experience. Setting out the reasonable water seal layout on paper by computation is very necessary.With reference to the engineering project, in this paper, mainly study on water seal layout of power station in river channel, the 3-D finite element model is boiled and static and dynamic stress were calculated, contrasted stress distribution of differ water seal layout Setting out the reasonable water seal layout, offer reference for engineering design and save the investment.By computational analysis gotten out: the reasonable water seal layout is efficiency for modify the stress state of water inlet, pier, spiral case, draft tube, tail water outlet, etc. Satisfied operating requirement and other design specification, the water seal in upstream should be moved to downstream and the water seal in downstream should be moved to upstream as so far as possible, the level water seal should be drive up proper, lead to balance between inside and outside of channel. Because of water seal layout in the two transverse joint of power house monolith are different, the surface of water filled is different so, the water pressure is not balance, always lead to the whole power house monolith subjected to torsion, so the stress of corner brim at water inlet and tail water outlet is greater, thus, should adjust the water seal layout in the two transverse joint, making the water pressure approximate equilibrium in both side, that can modify the stress state effective. For the larger unit capacity power station, the water seal layout in joint should carry out dynamic stress check computation, can’t just consider for static stress aspect.更多还原