簡介
鳳灘水(shui)(shui)電(dian)站(zhan)位于(yu)中國湖南省沅(yuan)陵縣、沅(yuan)水(shui)(shui)支流(liu)酉水(shui)(shui)下游,距(ju)沅(yuan)陵縣45km。混凝土空腹重力拱壩,最大壩高112.5m,校核洪水(shui)(shui)位時(shi)總庫容(rong)17.33億(yi)m3,1970年(nian)(nian)10月(yue)開工(gong)(gong),1978年(nian)(nian)5月(yue)第一(yi)臺機(ji)組發電(dian),1979年(nian)(nian)完工(gong)(gong)。老廠裝機(ji)容(rong)量40萬(wan)kW,保證出力10.3萬(wan)kW,多年(nian)(nian)平均(jun)發電(dian)量20.43億(yi)kW·h,2004年(nian)(nian)左岸(an)擴機(ji)兩臺20萬(wan)kW機(ji)組投運(yun),隨后進行老廠2號機(ji)組增容(rong)工(gong)(gong)程,總裝機(ji)容(rong)量達(da)到81.5萬(wan)kW。以發電(dian)為主(zhu),兼顧防洪、航運(yun)、灌溉、養殖(zhi)等。
結構
壩址為"U"形(xing)河(he)谷,枯水(shui)(shui)(shui)期河(he)床(chuang)寬(kuan)140m,河(he)床(chuang)右側礁石灘寬(kuan)100m,地層為前震旦系(xi)板溪砂巖夾少量(liang)板巖,巖性致密堅硬,但斷層、節理(li)發育。地震烈度(du)為5度(du)。 壩址以(yi)上流域面積17500平(ping)(ping)方(fang)公(gong)里,多年(nian)平(ping)(ping)均(jun)流量(liang)504立(li)(li)方(fang)米(mi)/秒(miao),實測最大流量(liang)16900立(li)(li)方(fang)米(mi)/秒(miao),多年(nian)平(ping)(ping)均(jun)輸(shu)沙量(liang)352萬立(li)(li)方(fang)米(mi)。千年(nian)一遇設計(ji)洪(hong)(hong)水(shui)(shui)(shui)流量(liang)29400立(li)(li)方(fang)米(mi)/秒(miao),相(xiang)(xiang)應洪(hong)(hong)水(shui)(shui)(shui)位209.56m,5000年(nian)一遇校(xiao)核(he)洪(hong)(hong)水(shui)(shui)(shui)流量(liang)34800立(li)(li)方(fang)米(mi)/秒(miao),相(xiang)(xiang)應洪(hong)(hong)水(shui)(shui)(shui)位221.4m,相(xiang)(xiang)應庫(ku)容(rong)17.33億(yi)(yi)立(li)(li)方(fang)米(mi)。正常蓄(xu)水(shui)(shui)(shui)位205m,相(xiang)(xiang)應庫(ku)容(rong)13.9億(yi)(yi)立(li)(li)方(fang)米(mi),死水(shui)(shui)(shui)位170m,相(xiang)(xiang)應庫(ku)容(rong)3.3億(yi)(yi)立(li)(li)方(fang)米(mi),調節庫(ku)容(rong)10.6億(yi)(yi)立(li)(li)方(fang)米(mi)。汛期防(fang)洪(hong)(hong)控(kong)制水(shui)(shui)(shui)位198.5m,防(fang)洪(hong)(hong)庫(ku)容(rong)6.22億(yi)(yi)立(li)(li)方(fang)米(mi)。水(shui)(shui)(shui)庫(ku)淹(yan)沒耕(geng)地495公(gong)頃。遷移人(ren)口1.1萬人(ren)。
樞紐布置
樞紐建筑物包括混凝土空(kong)腹拱壩、放(fang)空(kong)兼泄(xie)洪底孔,壩內廠房和過(guo)船過(guo)木筏道。
空腹重力拱壩
壩(ba)(ba)(ba)(ba)(ba)頂(ding)(ding)高(gao)(gao)(gao)程(cheng)221.5m,壩(ba)(ba)(ba)(ba)(ba)頂(ding)(ding)弧長488m,為(wei)(wei)定(ding)圓(yuan)心(xin)定(ding)半(ban)徑拱(gong)。大壩(ba)(ba)(ba)(ba)(ba)共分27個壩(ba)(ba)(ba)(ba)(ba)段(duan)(duan),拱(gong)冠左側(ce)為(wei)(wei)廠(chang)(chang)房壩(ba)(ba)(ba)(ba)(ba)段(duan)(duan),位(wei)于枯水河(he)槽,最(zui)大壩(ba)(ba)(ba)(ba)(ba)高(gao)(gao)(gao)112.5m,最(zui)大底寬(kuan)(kuan)60.44m;拱(gong)冠右側(ce)為(wei)(wei)溢(yi)流壩(ba)(ba)(ba)(ba)(ba)段(duan)(duan),位(wei)于河(he)床礁石灘上,最(zui)大壩(ba)(ba)(ba)(ba)(ba)高(gao)(gao)(gao)106.5m,最(zui)大底寬(kuan)(kuan)59.5m;兩岸(an)為(wei)(wei)非溢(yi)流壩(ba)(ba)(ba)(ba)(ba)段(duan)(duan)。壩(ba)(ba)(ba)(ba)(ba)內空(kong)(kong)(kong)腹沿壩(ba)(ba)(ba)(ba)(ba)軸線(xian)長255.8m。廠(chang)(chang)房壩(ba)(ba)(ba)(ba)(ba)段(duan)(duan)空(kong)(kong)(kong)腹高(gao)(gao)(gao)40.1m,寬(kuan)(kuan)20.5m。溢(yi)流壩(ba)(ba)(ba)(ba)(ba)段(duan)(duan)空(kong)(kong)(kong)腹寬(kuan)(kuan)28m,壩(ba)(ba)(ba)(ba)(ba)前腿寬(kuan)(kuan)20m,壩(ba)(ba)(ba)(ba)(ba)后腿寬(kuan)(kuan)11.5m。空(kong)(kong)(kong)腹斷面(mian)為(wei)(wei)橢圓(yuan)曲線(xian),橢圓(yuan)長軸基(ji)本上與荷(he)載(zai)的合(he)力平行,向上游傾斜(xie)。為(wei)(wei)便于施工(gong),空(kong)(kong)(kong)腹拱(gong)頂(ding)(ding)由一個兩心(xin)圓(yuan)曲線(xian)組成,空(kong)(kong)(kong)腹高(gao)(gao)(gao)度控制在約1/3壩(ba)(ba)(ba)(ba)(ba)高(gao)(gao)(gao),頂(ding)(ding)點高(gao)(gao)(gao)程(cheng)139.1m。采用空(kong)(kong)(kong)腹重力拱(gong)壩(ba)(ba)(ba)(ba)(ba)除(chu)了能(neng)協調泄洪與廠(chang)(chang)房布置(zhi)的矛盾,節省工(gong)程(cheng)量外,其本身特點是改善了壩(ba)(ba)(ba)(ba)(ba)體應(ying)力,使超載(zai)能(neng)力增大,有利(li)于壩(ba)(ba)(ba)(ba)(ba)基(ji)排水和(he)混凝土散熱降溫。
放空兼泄洪底孔
溢(yi)洪(hong)道布(bu)置(zhi)在8~12號壩(ba)(ba)段(duan)(廠房壩(ba)(ba)段(duan))和12~20號壩(ba)(ba)段(duan)(溢(yi)流(liu)(liu)壩(ba)(ba)段(duan))上。溢(yi)洪(hong)道凈寬182m,堰(yan)頂高(gao)程193m,共有(you)(you)13孔(kong),裝有(you)(you)寬14m、高(gao)13.13m的(de)弧形(xing)鋼閘門,最(zui)大單寬流(liu)(liu)量170立方米(mi)(mi)/秒(miao)。為了(le)減少水流(liu)(liu)及(ji)回流(liu)(liu)淘刷壩(ba)(ba)腳(jiao),壩(ba)(ba)下(xia)(xia)采用了(le)兩岸混凝土(tu)護(hu)坡和河床護(hu)坦等(deng)措施。為了(le)防止下(xia)(xia)泄量大時(shi)(shi)出(chu)現水流(liu)(liu)集中,下(xia)(xia)游沖刷加劇現象,并(bing)考慮下(xia)(xia)游水墊淺、地(di)質條件不利、抗沖能力低的(de)情況,采用高(gao)低坎(kan)(kan)空(kong)中碰擊消能方式,6孔(kong)高(gao)坎(kan)(kan),7孔(kong)低坎(kan)(kan),相間布(bu)置(zhi),挑(tiao)(tiao)坎(kan)(kan)高(gao)差達28m。低挑(tiao)(tiao)坎(kan)(kan)為連續式,高(gao)挑(tiao)(tiao)坎(kan)(kan)為舌式擴散型。泄洪(hong)時(shi)(shi)形(xing)成上下(xia)(xia)兩層水流(liu)(liu),在橫向和縱(zong)向(空(kong)中)碰撞,強烈(lie)擾動,擴散摻氣(qi),消能效果(guo)良好(hao)。 在右岸21號壩(ba)(ba)段(duan)設有(you)(you)一個放空(kong)兼泄水底(di)孔(kong),矩形(xing)進水口,斷(duan)(duan)面(mian)尺寸為6m×12m,進口底(di)坎(kan)(kan)高(gao)程145m,進口設平(ping)板事故檢(jian)修門,出(chu)口設弧形(xing)工(gong)作門,斷(duan)(duan)面(mian)尺寸6m×7m。死(si)水位時(shi)(shi)泄量為812立方米(mi)(mi)/秒(miao);校核洪(hong)水時(shi)(shi),可輔助溢(yi)洪(hong)道宣泄流(liu)(liu)量1280立方米(mi)(mi)/秒(miao)。
壩內廠房
壩內(nei)式廠房布置在(zai)(zai)9~12號壩段空腹內(nei),廠房長(chang)85m,寬20.5m,高40.1m,裝有4臺(tai)10萬kW混流式發電(dian)(dian)機(ji)組(zu)。水(shui)輪機(ji)為HL702-LJ-410型,轉輪直(zhi)徑(jing)4.1m。引(yin)(yin)(yin)水(shui)系統(tong)采用深井式引(yin)(yin)(yin)水(shui)道,單機(ji)單管(guan)引(yin)(yin)(yin)水(shui),進水(shui)口布置在(zai)(zai)9~12號壩段的溢(yi)流壩閘墩(dun)首部,4根直(zhi)徑(jing)5.6m的壓(ya)力鋼(gang)管(guan)沿上游面(mian)垂直(zhi)下降,然后水(shui)平(ping)穿過壩體。主廠房右側布置220kV開關(guan)站(zhan)(zhan)及2臺(tai)220kV自(zi)耦變壓(ya)器。第一副廠房和110kV變電(dian)(dian)開關(guan)站(zhan)(zhan)布置在(zai)(zai)左岸非溢(yi)流壩后。
過船過木筏道
船(chuan)、筏道(dao)布(bu)置(zhi)于右(you)岸(an)(an)非溢流(liu)壩(ba)段,沿(yan)右(you)岸(an)(an)山坡布(bu)置(zhi),采用(yong)雙(shuang)重垂直(zhi)橋(qiao)吊加斜面升船(chuan)機的(de)綜合(he)方案(an)。上游通航(hang)水(shui)位205~170m,下游通航(hang)水(shui)位114.2~117.36m。可通過50t級(ji)船(chuan)只,年過壩(ba)能力為木材10萬t,貨物(wu)10萬t。2條直(zhi)徑(jing)1.6m的(de)灌(guan)溉引水(shui)管布(bu)置(zhi)在右(you)岸(an)(an)21~22號壩(ba)段內,引用(yong)流(liu)量(liang)為8立(li)方米/秒。
工程施工
工程總(zong)量為土石方(fang)(fang)開挖61萬(wan)立方(fang)(fang)米(mi),混凝(ning)土澆筑122.8萬(wan)立方(fang)(fang)米(mi),鋼筋及鋼材用(yong)量2.03萬(wan)t。 采用(yong)二(er)期施(shi)工,第一期由明(ming)渠導流(liu),第二(er)期由壩(ba)體導流(liu)底孔過流(liu)。在空(kong)腹(fu)封拱(gong)和(he)(he)廠房拱(gong)頂(ding)施(shi)工時(shi)采用(yong)預制拱(gong)肋和(he)(he)拱(gong)架,其跨度達15.35m,重量分別(bie)3.85t和(he)(he)9t,按(an)雙鉸拱(gong)設計,用(yong)10t門(men)機吊裝(zhuang)就位于大(da)壩(ba)伸出的(de)牛腿上,上鋪預制板(ban)后(hou)進行拱(gong)頂(ding)混凝(ning)土澆筑。 施(shi)工過程中發生過圍堰被(bei)沖(chong)毀和(he)(he)副廠房進水、發電機被(bei)淹等事故(gu)。1980年8月4日大(da)壩(ba)下泄12500立方(fang)(fang)米(mi)/秒時(shi),沖(chong)壞了下游兩岸(an)公路。