簡介
鳳(feng)灘水(shui)電(dian)站位(wei)于中(zhong)國湖南省(sheng)沅(yuan)陵縣、沅(yuan)水(shui)支(zhi)流酉(you)水(shui)下游,距沅(yuan)陵縣45km。混(hun)凝土空腹重力(li)拱(gong)壩,最大(da)壩高112.5m,校核洪(hong)水(shui)位(wei)時總(zong)庫(ku)容(rong)17.33億m3,1970年(nian)(nian)10月(yue)開工,1978年(nian)(nian)5月(yue)第一臺機(ji)組發電(dian),1979年(nian)(nian)完工。老廠裝機(ji)容(rong)量40萬(wan)(wan)kW,保證出力(li)10.3萬(wan)(wan)kW,多(duo)年(nian)(nian)平均發電(dian)量20.43億kW·h,2004年(nian)(nian)左(zuo)岸擴機(ji)兩(liang)臺20萬(wan)(wan)kW機(ji)組投(tou)運(yun),隨后(hou)進行老廠2號機(ji)組增容(rong)工程(cheng),總(zong)裝機(ji)容(rong)量達到81.5萬(wan)(wan)kW。以發電(dian)為主,兼顧防洪(hong)、航運(yun)、灌溉(gai)、養殖等。
結構
壩址為(wei)(wei)"U"形(xing)河谷,枯(ku)水(shui)期(qi)河床寬140m,河床右側礁(jiao)石(shi)灘(tan)寬100m,地(di)(di)層(ceng)為(wei)(wei)前震旦系(xi)板溪砂(sha)巖(yan)夾少量(liang)(liang)(liang)(liang)(liang)板巖(yan),巖(yan)性致(zhi)密堅硬,但(dan)斷層(ceng)、節理(li)發育。地(di)(di)震烈度為(wei)(wei)5度。 壩址以上流(liu)域面(mian)積17500平方(fang)(fang)公(gong)(gong)里(li),多年(nian)平均流(liu)量(liang)(liang)(liang)(liang)(liang)504立(li)方(fang)(fang)米(mi)/秒(miao),實測最大流(liu)量(liang)(liang)(liang)(liang)(liang)16900立(li)方(fang)(fang)米(mi)/秒(miao),多年(nian)平均輸沙量(liang)(liang)(liang)(liang)(liang)352萬(wan)(wan)立(li)方(fang)(fang)米(mi)。千年(nian)一遇(yu)設計(ji)洪(hong)水(shui)流(liu)量(liang)(liang)(liang)(liang)(liang)29400立(li)方(fang)(fang)米(mi)/秒(miao),相(xiang)應(ying)(ying)洪(hong)水(shui)位209.56m,5000年(nian)一遇(yu)校(xiao)核洪(hong)水(shui)流(liu)量(liang)(liang)(liang)(liang)(liang)34800立(li)方(fang)(fang)米(mi)/秒(miao),相(xiang)應(ying)(ying)洪(hong)水(shui)位221.4m,相(xiang)應(ying)(ying)庫容(rong)(rong)(rong)17.33億(yi)(yi)立(li)方(fang)(fang)米(mi)。正常蓄水(shui)位205m,相(xiang)應(ying)(ying)庫容(rong)(rong)(rong)13.9億(yi)(yi)立(li)方(fang)(fang)米(mi),死水(shui)位170m,相(xiang)應(ying)(ying)庫容(rong)(rong)(rong)3.3億(yi)(yi)立(li)方(fang)(fang)米(mi),調節庫容(rong)(rong)(rong)10.6億(yi)(yi)立(li)方(fang)(fang)米(mi)。汛(xun)期(qi)防洪(hong)控制水(shui)位198.5m,防洪(hong)庫容(rong)(rong)(rong)6.22億(yi)(yi)立(li)方(fang)(fang)米(mi)。水(shui)庫淹沒耕(geng)地(di)(di)495公(gong)(gong)頃。遷移人口(kou)1.1萬(wan)(wan)人。
樞紐布置
樞(shu)紐建筑物(wu)包括混凝土空腹拱壩(ba)、放空兼(jian)泄(xie)洪底孔,壩(ba)內廠房和(he)過船過木筏(fa)道。
空腹重力拱壩
壩(ba)(ba)(ba)(ba)(ba)頂(ding)高(gao)程(cheng)221.5m,壩(ba)(ba)(ba)(ba)(ba)頂(ding)弧長488m,為(wei)定圓心定半徑拱(gong)(gong)。大(da)壩(ba)(ba)(ba)(ba)(ba)共分27個(ge)壩(ba)(ba)(ba)(ba)(ba)段(duan),拱(gong)(gong)冠左(zuo)側為(wei)廠房(fang)壩(ba)(ba)(ba)(ba)(ba)段(duan),位于(yu)枯(ku)水(shui)河槽,最大(da)壩(ba)(ba)(ba)(ba)(ba)高(gao)112.5m,最大(da)底寬60.44m;拱(gong)(gong)冠右側為(wei)溢流壩(ba)(ba)(ba)(ba)(ba)段(duan),位于(yu)河床礁(jiao)石灘上,最大(da)壩(ba)(ba)(ba)(ba)(ba)高(gao)106.5m,最大(da)底寬59.5m;兩(liang)(liang)岸為(wei)非溢流壩(ba)(ba)(ba)(ba)(ba)段(duan)。壩(ba)(ba)(ba)(ba)(ba)內空(kong)腹(fu)沿壩(ba)(ba)(ba)(ba)(ba)軸(zhou)線(xian)長255.8m。廠房(fang)壩(ba)(ba)(ba)(ba)(ba)段(duan)空(kong)腹(fu)高(gao)40.1m,寬20.5m。溢流壩(ba)(ba)(ba)(ba)(ba)段(duan)空(kong)腹(fu)寬28m,壩(ba)(ba)(ba)(ba)(ba)前腿(tui)寬20m,壩(ba)(ba)(ba)(ba)(ba)后腿(tui)寬11.5m。空(kong)腹(fu)斷面為(wei)橢圓曲線(xian),橢圓長軸(zhou)基本上與荷載的(de)合力(li)平行,向(xiang)上游傾斜。為(wei)便于(yu)施工,空(kong)腹(fu)拱(gong)(gong)頂(ding)由一個(ge)兩(liang)(liang)心圓曲線(xian)組成(cheng),空(kong)腹(fu)高(gao)度(du)控制在約1/3壩(ba)(ba)(ba)(ba)(ba)高(gao),頂(ding)點(dian)高(gao)程(cheng)139.1m。采用空(kong)腹(fu)重力(li)拱(gong)(gong)壩(ba)(ba)(ba)(ba)(ba)除了能協(xie)調泄洪與廠房(fang)布置的(de)矛(mao)盾,節省工程(cheng)量外(wai),其本身(shen)特點(dian)是改善了壩(ba)(ba)(ba)(ba)(ba)體(ti)應力(li),使超載能力(li)增大(da),有(you)利(li)于(yu)壩(ba)(ba)(ba)(ba)(ba)基排水(shui)和混凝土散熱(re)降溫。
放空兼泄洪底孔
溢洪(hong)道(dao)布置(zhi)在8~12號壩(ba)段(duan)(廠房壩(ba)段(duan))和(he)12~20號壩(ba)段(duan)(溢流(liu)壩(ba)段(duan))上。溢洪(hong)道(dao)凈寬182m,堰(yan)頂高(gao)程193m,共有13孔(kong)(kong),裝有寬14m、高(gao)13.13m的弧形(xing)鋼閘門,最大單(dan)寬流(liu)量170立方米/秒(miao)。為(wei)(wei)了減少水(shui)(shui)流(liu)及回流(liu)淘刷壩(ba)腳,壩(ba)下(xia)采(cai)用(yong)了兩(liang)岸(an)混凝土護(hu)坡(po)和(he)河床護(hu)坦等措施。為(wei)(wei)了防止下(xia)泄量大時(shi)(shi)出現水(shui)(shui)流(liu)集中(zhong),下(xia)游沖刷加劇現象(xiang),并考慮下(xia)游水(shui)(shui)墊淺(qian)、地質條件不利、抗沖能力低(di)(di)的情況,采(cai)用(yong)高(gao)低(di)(di)坎(kan)(kan)(kan)空(kong)中(zhong)碰擊消(xiao)能方式(shi),6孔(kong)(kong)高(gao)坎(kan)(kan)(kan),7孔(kong)(kong)低(di)(di)坎(kan)(kan)(kan),相間(jian)布置(zhi),挑(tiao)坎(kan)(kan)(kan)高(gao)差達(da)28m。低(di)(di)挑(tiao)坎(kan)(kan)(kan)為(wei)(wei)連續式(shi),高(gao)挑(tiao)坎(kan)(kan)(kan)為(wei)(wei)舌式(shi)擴散型。泄洪(hong)時(shi)(shi)形(xing)成上下(xia)兩(liang)層水(shui)(shui)流(liu),在橫向(xiang)和(he)縱向(xiang)(空(kong)中(zhong))碰撞,強(qiang)烈(lie)擾動(dong),擴散摻(chan)氣,消(xiao)能效果良好(hao)。 在右岸(an)21號壩(ba)段(duan)設(she)有一個放空(kong)兼泄水(shui)(shui)底(di)孔(kong)(kong),矩形(xing)進(jin)水(shui)(shui)口,斷面尺寸為(wei)(wei)6m×12m,進(jin)口底(di)坎(kan)(kan)(kan)高(gao)程145m,進(jin)口設(she)平板事(shi)故檢修門,出口設(she)弧形(xing)工作(zuo)門,斷面尺寸6m×7m。死水(shui)(shui)位時(shi)(shi)泄量為(wei)(wei)812立方米/秒(miao);校(xiao)核洪(hong)水(shui)(shui)時(shi)(shi),可輔助溢洪(hong)道(dao)宣(xuan)泄流(liu)量1280立方米/秒(miao)。
壩內廠房
壩內(nei)式廠(chang)房(fang)布(bu)置在9~12號(hao)壩段(duan)空(kong)腹內(nei),廠(chang)房(fang)長(chang)85m,寬20.5m,高40.1m,裝有4臺(tai)10萬kW混(hun)流式發電機組。水(shui)(shui)輪機為HL702-LJ-410型,轉(zhuan)輪直(zhi)徑4.1m。引(yin)水(shui)(shui)系(xi)統采用深(shen)井式引(yin)水(shui)(shui)道,單機單管引(yin)水(shui)(shui),進水(shui)(shui)口布(bu)置在9~12號(hao)壩段(duan)的(de)(de)溢(yi)流壩閘墩(dun)首部,4根直(zhi)徑5.6m的(de)(de)壓(ya)力鋼(gang)管沿上游面垂(chui)直(zhi)下降,然后水(shui)(shui)平穿(chuan)過壩體。主(zhu)廠(chang)房(fang)右側布(bu)置220kV開關(guan)站及(ji)2臺(tai)220kV自(zi)耦變壓(ya)器。第一副廠(chang)房(fang)和110kV變電開關(guan)站布(bu)置在左(zuo)岸非溢(yi)流壩后。
過船過木筏道
船、筏道布置于(yu)右岸非(fei)溢流(liu)壩(ba)段(duan),沿右岸山坡(po)布置,采用(yong)雙(shuang)重垂直(zhi)橋(qiao)吊(diao)加(jia)斜面升(sheng)船機的(de)綜(zong)合方(fang)案。上(shang)游通航水位205~170m,下(xia)游通航水位114.2~117.36m。可通過(guo)50t級船只,年過(guo)壩(ba)能(neng)力為木材10萬t,貨物(wu)10萬t。2條直(zhi)徑1.6m的(de)灌溉引水管布置在右岸21~22號壩(ba)段(duan)內,引用(yong)流(liu)量為8立方(fang)米(mi)/秒。
工程施工
工(gong)程(cheng)總(zong)量(liang)為土石(shi)方(fang)開挖61萬(wan)立(li)方(fang)米,混凝土澆筑122.8萬(wan)立(li)方(fang)米,鋼(gang)筋及鋼(gang)材用量(liang)2.03萬(wan)t。 采(cai)(cai)用二期施工(gong),第一期由(you)明渠導(dao)流(liu)(liu),第二期由(you)壩體導(dao)流(liu)(liu)底孔過(guo)流(liu)(liu)。在(zai)空(kong)腹封拱和(he)(he)廠(chang)房拱頂(ding)施工(gong)時采(cai)(cai)用預制(zhi)拱肋和(he)(he)拱架,其(qi)跨度達15.35m,重(zhong)量(liang)分別3.85t和(he)(he)9t,按雙鉸拱設計,用10t門(men)機吊裝就位于大壩伸出的牛腿上(shang),上(shang)鋪預制(zhi)板(ban)后(hou)進行拱頂(ding)混凝土澆筑。 施工(gong)過(guo)程(cheng)中發(fa)生過(guo)圍(wei)堰被沖毀(hui)和(he)(he)副(fu)廠(chang)房進水、發(fa)電機被淹等事故(gu)。1980年8月(yue)4日大壩下(xia)泄12500立(li)方(fang)米/秒時,沖壞了下(xia)游(you)兩岸(an)公路(lu)。