天生橋一(yi)級(ji)水電(dian)站為(wei)西電(dian)東送的重點工程(cheng),也是珠(zhu)江流域西江水系上游的南盤江龍頭電(dian)站,電(dian)站總裝(zhuang)機(ji)容量為(wei)1200MW(4×300MW),電(dian)站于(yu)1998年(nian)底首(shou)臺機(ji)組發電(dian),至(zhi)2000年(nian)工程(cheng)竣工。
工程特征
溢洪道布(bu)置于右岸埡口處,其開挖料為(wei)(wei)大(da)壩填筑的(de)主要料源。溢洪道設計標準為(wei)(wei)千年一遇洪水(Q=20900m3/s)設計,可能(neng)最大(da)洪水(Q=28500m3/s)校核。經(jing)水庫(ku)調洪后,相應的(de)下泄流(liu)量分別(bie)為(wei)(wei)14782m3/s和21750m3/s。泄洪孔口尺寸為(wei)(wei)寬(kuan)13m,高20m,共5孔。
溢洪道全長(chang)1665m,由引(yin)渠(qu)(qu)、溢流(liu)(liu)(liu)堰(yan)(yan)、泄(xie)(xie)槽(cao)(cao)、挑流(liu)(liu)(liu)鼻坎(kan)(kan)和護岸工程(cheng)(cheng)(cheng)組成。引(yin)渠(qu)(qu)長(chang)1122m,底寬120m,渠(qu)(qu)底高(gao)程(cheng)(cheng)(cheng)745m,底坡i=0。渠(qu)(qu)道兩(liang)側(ce)為(wei)垂直邊坡,每隔22m高(gao)設1條12m寬的馬道,引(yin)渠(qu)(qu)基本不襯砌。溢流(liu)(liu)(liu)堰(yan)(yan)頂高(gao)程(cheng)(cheng)(cheng)760m,設5孔寬13m高(gao)20m的弧形閘門(men),溢流(liu)(liu)(liu)前緣總(zong)長(chang)81m。堰(yan)(yan)后為(wei)泄(xie)(xie)槽(cao)(cao),泄(xie)(xie)槽(cao)(cao)平(ping)面采用(yong)不對稱收縮體型,橫斷面為(wei)矩形,縱坡i=13%。為(wei)避免氣蝕破(po)壞,在(zai)泄(xie)(xie)槽(cao)(cao)段共設5道摻氣槽(cao)(cao)。泄(xie)(xie)槽(cao)(cao)軸(zhou)線與下游河(he)道的交角為(wei)50°~60°,且(qie)流(liu)(liu)(liu)速高(gao),泄(xie)(xie)量大(da),泄(xie)(xie)洪功(gong)率達2800萬(wan)kW。經(jing)水(shui)力(li)模(mo)型試驗研究,選用(yong)左槽(cao)(cao)正向(xiang)擴(kuo)散連(lian)續大(da)挑角鼻坎(kan)(kan)和右槽(cao)(cao)窄縫曲面貼角斜鼻坎(kan)(kan)的結合(he)方案(an)(an)(an),較(jiao)好地解決了泄(xie)(xie)流(liu)(liu)(liu)消能問題。在(zai)工程(cheng)(cheng)(cheng)建設過程(cheng)(cheng)(cheng)中,對上述設計(ji)方案(an)(an)(an)做(zuo)了簡化,取消了泄(xie)(xie)槽(cao)(cao)中隔墩;又經(jing)水(shui)力(li)模(mo)型試驗,選取了兩(liang)側(ce)擴(kuo)散的舌形鼻坎(kan)(kan)方案(an)(an)(an),在(zai)出口(kou)河(he)岸相(xiang)應地做(zuo)了保護。
引水發電系統
引水(shui)發電系(xi)統位于左岸砂泥巖地區。進水(shui)口設(she)在左岸8號沖溝(gou)內,10號沖溝(gou)下游側布(bu)置地面廠房(fang),采(cai)用單(dan)機單(dan)管布(bu)置。
引(yin)水(shui)(shui)(shui)系統包括引(yin)渠、進水(shui)(shui)(shui)口、引(yin)水(shui)(shui)(shui)隧(sui)洞(dong)和壓(ya)力(li)鋼管(guan)(guan)道。根據進水(shui)(shui)(shui)口的(de)布置,傍山開挖形(xing)(xing)成引(yin)渠。引(yin)渠沿中心線長(chang)度為284m,梯形(xing)(xing)復式斷(duan)面。其(qi)底(di)板寬98m,高程710m。進水(shui)(shui)(shui)口采用(yong)岸邊塔(ta)式,進水(shui)(shui)(shui)塔(ta)長(chang)98m,寬27.5m,高84m。設置2道直柵槽,內設16扇(shan)攔污柵,1扇(shan)檢修(xiu)門及(ji)4扇(shan)事(shi)故門。對(dui)外通過(guo)塔(ta)頂交通橋與左岸公(gong)路(lu)相連(lian)。引(yin)水(shui)(shui)(shui)隧(sui)洞(dong)4條(tiao),中心距(ju)24m,內徑9.6m,縱坡7.5%~10%,水(shui)(shui)(shui)平(ping)投影長(chang)380.39~494.09m。結構設計采用(yong)一次支護和二次襯(chen)砌形(xing)(xing)式,局部過(guo)溝地段二次支護改(gai)用(yong)后張法(fa)預應力(li)混凝土襯(chen)砌。壓(ya)力(li)鋼管(guan)(guan)道4條(tiao),中心距(ju)23.1m,采用(yong)斜(xie)井(jing)布置,坡度50°,由(you)上(shang)彎管(guan)(guan)、斜(xie)井(jing)管(guan)(guan)、下彎管(guan)(guan)和水(shui)(shui)(shui)平(ping)管(guan)(guan)組成。鋼管(guan)(guan)內徑7~8.2m,水(shui)(shui)(shui)平(ping)投影長(chang)158.78~172.19m,管(guan)(guan)壁(bi)厚22~30mm。
地面廠房
地面(mian)廠房位于左岸10號(hao)沖溝(gou)下游側,順(shun)河向(xiang)布置。廠區后(hou)山坡(po)(po)臨時邊坡(po)(po)高(gao)達154m,永(yong)久邊坡(po)(po)高(gao)達109m,并(bing)有斷層(ceng)和向(xiang)背斜結構面(mian),對邊坡(po)(po)穩定有影響(xiang)。為此做了大量邊坡(po)(po)穩定分析,采取了邊坡(po)(po)綜合治(zhi)理措施,并(bing)設置了監測系統(tong)。
主廠(chang)(chang)(chang)(chang)(chang)(chang)房(fang)(fang)長154.4m,寬26m,高(gao)67m。廠(chang)(chang)(chang)(chang)(chang)(chang)房(fang)(fang)內安裝(zhuang)4臺單機(ji)容量為(wei)300MW的(de)水輪(lun)發電機(ji)組,其安裝(zhuang)高(gao)程(cheng)為(wei)633.5m。上(shang)(shang)游(you)(you)側(ce)(ce)副(fu)廠(chang)(chang)(chang)(chang)(chang)(chang)房(fang)(fang)布置電氣設備,下(xia)游(you)(you)側(ce)(ce)副(fu)廠(chang)(chang)(chang)(chang)(chang)(chang)房(fang)(fang)布置水輪(lun)機(ji)設備,端頭副(fu)廠(chang)(chang)(chang)(chang)(chang)(chang)房(fang)(fang)為(wei)中控室及計算機(ji)監控設備。主變壓器布置在上(shang)(shang)游(you)(you)側(ce)(ce)副(fu)廠(chang)(chang)(chang)(chang)(chang)(chang)房(fang)(fang)的(de)上(shang)(shang)游(you)(you),出線架位(wei)于上(shang)(shang)游(you)(you)副(fu)廠(chang)(chang)(chang)(chang)(chang)(chang)房(fang)(fang)屋頂上(shang)(shang),4回220kV出線至換(huan)流站。
放空隧洞
放(fang)空隧洞(dong)(dong)位于(yu)右(you)岸(an)1號(hao)沖溝(gou)的(de)下游側,全長(chang)1062.17m,進口(kou)高程為660m,具有(you)(you)施工(gong)(gong)(gong)期參與后(hou)期導流、水(shui)(shui)庫(ku)蓄水(shui)(shui)期向下游電(dian)站供水(shui)(shui)、運行期放(fang)空水(shui)(shui)庫(ku)檢修(xiu)大(da)壩面板等(deng)功能。距(ju)放(fang)空隧洞(dong)(dong)進口(kou)339.17m處設事(shi)故閘(zha)門(men)(men)并(bing)(bing),并(bing)(bing)高131m,內(nei)徑11.4m,內(nei)設6.8m×9m的(de)事(shi)故平板鏈(lian)輪閘(zha)門(men)(men);距(ju)進口(kou)560.67m處為工(gong)(gong)(gong)作(zuo)閘(zha)門(men)(men)室(shi),內(nei)設6.4m×7.5m的(de)工(gong)(gong)(gong)作(zuo)弧形(xing)閘(zha)門(men)(men);工(gong)(gong)(gong)作(zuo)閘(zha)門(men)(men)室(shi)之前為圓形(xing)有(you)(you)壓隧洞(dong)(dong),長(chang)557.67m。內(nei)徑9.6m;其(qi)后(hou)為方(fang)圓形(xing)無(wu)壓隧洞(dong)(dong),長(chang)489.5m,寬8m,高11m;洞(dong)(dong)后(hou)接長(chang)約162m的(de)出口(kou)明渠及挑流鼻坎。
事(shi)故閘門(men)(men)井以交通(tong)(tong)(tong)便橋與右(you)壩頭相接;工作閘門(men)(men)室以交通(tong)(tong)(tong)通(tong)(tong)(tong)風(feng)(feng)洞(dong)與場內公路相連(lian)。交通(tong)(tong)(tong)通(tong)(tong)(tong)風(feng)(feng)洞(dong)布置在放(fang)空洞(dong)的(de)左(zuo)側(ce),為雙層(ceng)(ceng)結構,上層(ceng)(ceng)交通(tong)(tong)(tong),下層(ceng)(ceng)通(tong)(tong)(tong)風(feng)(feng)。
大壩安全監測
變形監測 3.1.1內(nei)部變形監測
變形監測
(l)觀測(ce)(ce)點布(bu)置大壩布(bu)置有(you)3個觀測(ce)(ce)斷面(mian)(mian),0+630斷面(mian)(mian)為(wei)河床中部(bu)最大斷面(mian)(mian),右岸0十438斷面(mian)(mian)在1/2壩高處,左岸0十918斷面(mian)(mian)位于地形突變部(bu)位。在觀測(ce)(ce)斷面(mian)(mian)的(de)665、692、725、758m高程,共布(bu)置有(you)沉(chen)降(jiang)測(ce)(ce)點50個,水平位移測(ce)(ce)點31個。
(2)觀(guan)測(ce)儀器(qi)壩體內部垂直(zhi)位移(yi)觀(guan)測(ce)采(cai)用水(shui)(shui)管式沉(chen)降儀,水(shui)(shui)平位移(yi)觀(guan)測(ce)采(cai)用引張線式水(shui)(shui)平位移(yi)計。天(tian)生橋大(da)壩安裝的(de)垂直(zhi)、水(shui)(shui)平位移(yi)計管線最大(da)長度達350m,堪(kan)稱(cheng)世界第一。
3.1.2面板撓度監(jian)測
面(mian)(mian)板(ban)撓度觀(guan)(guan)測(ce)(ce)(ce)通常采(cai)(cai)用(yong)埋設(she)測(ce)(ce)(ce)斜儀導管(guan)的(de)方(fang)法,用(yong)活動(dong)(dong)式測(ce)(ce)(ce)斜儀觀(guan)(guan)測(ce)(ce)(ce)導管(guan)的(de)撓度變(bian)(bian)形。大壩面(mian)(mian)板(ban)坡(po)長305m,如采(cai)(cai)用(yong)活動(dong)(dong)式測(ce)(ce)(ce)斜儀則存在以下問題:測(ce)(ce)(ce)繩太長可(ke)能產生(sheng)(sheng)測(ce)(ce)(ce)頭(tou)下放(fang)困難;采(cai)(cai)用(yong)測(ce)(ce)(ce)頭(tou)下放(fang)的(de)輔助(zhu)牽引裝(zhuang)置(zhi),又(you)耽心輔助(zhu)牽引裝(zhuang)置(zhi)一(yi)(yi)旦發生(sheng)(sheng)故障,很難檢修;觀(guan)(guan)測(ce)(ce)(ce)耗費時間很長,也難以實現觀(guan)(guan)測(ce)(ce)(ce)的(de)自動(dong)(dong)化(hua)等(deng)。承建(jian)(jian)單位的(de)巴西專家,根據辛戈壩的(de)經(jing)驗,建(jian)(jian)議采(cai)(cai)用(yong)電(dian)(dian)平(ping)器進(jin)行面(mian)(mian)板(ban)撓度觀(guan)(guan)測(ce)(ce)(ce),經(jing)參建(jian)(jian)各方(fang)認真(zhen)研究(jiu),這一(yi)(yi)建(jian)(jian)議得(de)到了采(cai)(cai)納。電(dian)(dian)平(ping)器是(shi)一(yi)(yi)種固定(ding)式測(ce)(ce)(ce)斜儀,觀(guan)(guan)測(ce)(ce)(ce)精度高,根據電(dian)(dian)平(ping)器觀(guan)(guan)測(ce)(ce)(ce)的(de)測(ce)(ce)(ce)點傾角變(bian)(bian)化(hua)可(ke)計算面(mian)(mian)板(ban)的(de)撓度曲線。天生(sheng)(sheng)橋大壩3個觀(guan)(guan)測(ce)(ce)(ce)斷面(mian)(mian)的(de)面(mian)(mian)板(ban)上游(you)共布置(zhi)64個電(dian)(dian)平(ping)器來觀(guan)(guan)測(ce)(ce)(ce)面(mian)(mian)板(ban)撓度變(bian)(bian)形。
3.1.3接(jie)縫監測
(1)周邊縫(feng)沿周邊縫(feng)布置(zhi)有12組三向測縫(feng)計,觀(guan)測縫(feng)面開度、沉降和(he)切向位移相對變化。
(2)垂直縫在(zai)面板垂直伸縮(suo)縫的張性縫區、張性縫和壓性縫過渡區,跨(kua)縫布置單向測(ce)縫計24支,用來觀測(ce)縫面開(kai)合變化(hua)。
(3)面(mian)板(ban)(ban)脫空(kong)(kong)觀(guan)測(ce)(ce)(ce)大(da)壩一期面(mian)板(ban)(ban)澆筑(zhu)后,檢查發(fa)現面(mian)板(ban)(ban)頂部與墊層(ceng)料(liao)間有大(da)面(mian)積(ji)脫空(kong)(kong),決定(ding)在二(er)期面(mian)板(ban)(ban)布置(zhi)(zhi)2組二(er)向(xiang)測(ce)(ce)(ce)縫計,觀(guan)測(ce)(ce)(ce)面(mian)板(ban)(ban)和墊層(ceng)料(liao)接觸(chu)縫面(mian)的(de)法(fa)向(xiang)和切向(xiang)變形;在三期面(mian)板(ban)(ban)布置(zhi)(zhi)7組觀(guan)測(ce)(ce)(ce)面(mian)板(ban)(ban)脫空(kong)(kong)變形的(de)二(er)向(xiang)測(ce)(ce)(ce)縫計。
3.1.4表面變(bian)形(xing)監測
在壩(ba)體上、下游(you)壩(ba)面和壩(ba)頂(ding),共布置(zhi)視(shi)準(zhun)線(xian)8條,其(qi)中布置(zhi)在一(yi)、二期面板頂(ding)部的視(shi)準(zhun)線(xian)為(wei)施工期臨(lin)時測(ce)線(xian),水平位(wei)移(yi)觀(guan)測(ce)采用視(shi)準(zhun)線(xian)法,垂直位(wei)移(yi)用水準(zhun)儀觀(guan)測(ce)。
滲流監測 3.2.1滲流壓力(li)監測
滲流監測
(1)壩體滲(shen)流壓力在距(ju)趾板“X”線下游3m的(de)墊層料區基礎面,布置(zhi)有坑埋式滲(shen)壓計13支,用來觀測周邊縫(feng)后壩體的(de)滲(shen)壓。
(2)壩基(ji)滲(shen)流壓力在(zai)趾板灌(guan)漿帷幕前(qian)后,布置有鉆孔式滲(shen)壓計21支,觀測壩基(ji)滲(shen)壓,了(le)解帷幕阻滲(shen)效果。
(3)繞(rao)壩(ba)滲流(liu)水位在左、右岸壩(ba)肩,共布置16個(ge)鉆孔測壓管(guan)觀測繞(rao)壩(ba)滲流(liu)水位。
3.2.2滲(shen)流量監(jian)測(ce)
大(da)壩(ba)下游布(bu)置(zhi)了1個(ge)滲(shen)流匯(hui)集(ji)系(xi)統。在下游壩(ba)腳設(she)置(zhi)1道截(jie)水(shui)墻(qiang),攔截(jie)壩(ba)體滲(shen)水(shui),使滲(shen)流匯(hui)集(ji),通過布(bu)置(zhi)在右岸的(de)引渠(qu)流向下游,在引渠(qu)設(she)置(zhi)量水(shui)堰(yan)(yan)觀測壩(ba)體滲(shen)流。在右岸壩(ba)肩排水(shui)系(xi)統的(de)2個(ge)洞口布(bu)置(zhi)了觀測壩(ba)肩滲(shen)流量的(de)量水(shui)堰(yan)(yan)。
壓(ya)力(li)、應力(li)和溫度(du)監測 3.3.1壓(ya)力(li)監測
壓力應力溫度
大(da)(da)壩(ba)0十(shi)630斷面(mian)4個(ge)不同高程(cheng)的面(mian)板與(yu)墊層(ceng)料(liao)接觸(chu)面(mian),布置(zhi)有觀測(ce)接觸(chu)土(tu)壓(ya)力的土(tu)壓(ya)力計(ji);在壩(ba)體過渡料(liao)中部和壩(ba)軸(zhou)線處,布置(zhi)有觀測(ce)平(ping)面(mian)應(ying)力變化的土(tu)壓(ya)力計(ji)。大(da)(da)壩(ba)共布置(zhi)土(tu)壓(ya)力計(ji)28支。
3.3.2混(hun)凝(ning)土面(mian)板(ban)應力和溫(wen)度監測(ce)
大(da)壩(ba)面(mian)板(ban)布(bu)置了應(ying)力應(ying)變觀(guan)測剖(pou)面(mian)6個(ge),溫度觀(guan)測剖(pou)面(mian)4個(ge),有(you)應(ying)變計84支(zhi)、無應(ying)力計15支(zhi)、鋼(gang)筋(jin)計55支(zhi)、溫度計27支(zhi),共(gong)計181支(zhi)儀器,用來(lai)觀(guan)測面(mian)板(ban)的應(ying)力、應(ying)變和溫度變化(hua)。
3.4地(di)震反應(ying)監測(ce)
大壩(ba)設置(zhi)了遙(yao)測微(wei)震(zhen)(zhen)臺網,記錄壩(ba)區和庫(ku)區地震(zhen)(zhen)情(qing)況;在壩(ba)體和基巖布置(zhi)強震(zhen)(zhen)儀監測壩(ba)體的地震(zhen)(zhen)反應。
運行概況
1998年(nian)8月(yue)天生橋一級電站水庫正式蓄(xu)水,同年(nian)最高水位(wei)達740.36m,發生時(shi)間為1998年(nian)11月(yue)8日,1998年(nian)12月(yue)一級電站首4#機組投產(chan)發電,此時(shi)大壩已(yi)完成堆石(shi)體(ti)填筑(787.3m)及三期面板澆筑,下游壩體(ti)經濟斷面于12月(yue)填筑到787.3m高程。
1999年(nian)水庫最高水位767.19m,為99年(nian)9月(yue)1日,大壩(ba)進行(xing)防浪(lang)墻及壩(ba)體(ti)787.3m~791.0m高程施工,99年(nian)12月(yue)3#機(ji)投入運行(xing)。
2000年(nian)水(shui)(shui)(shui)庫蓄(xu)水(shui)(shui)(shui)至(zhi)正常水(shui)(shui)(shui)位780.0m運(yun)行(xing)(10月(yue)17日(ri)),年(nian)底大壩施工全(quan)(quan)部完(wan)成,2000年(nian)9月(yue)2#機投(tou)(tou)入(ru)運(yun)行(xing),12月(yue)1#機投(tou)(tou)入(ru)運(yun)行(xing),至(zhi)此四臺機組全(quan)(quan)部投(tou)(tou)入(ru)運(yun)行(xing)。
2001年水(shui)庫蓄水(shui)至正常水(shui)位780.0m運行(11月11日),2002年水(shui)庫蓄水(shui)至776.96m運行(9月17日)。
運行特點
(1)天生橋一級(ji)(ji)水電站(zhan)為(wei)南盤江龍(long)頭電站(zhan),庫(ku)容大(da),大(da)壩(ba)為(wei)世(shi)界第(di)二(er)、亞(ya)州第(di)一高的面板堆石壩(ba),大(da)壩(ba)的安(an)全(quan)將對(dui)下游已建電站(zhan)(天生橋二(er)級(ji)(ji)、巖灘、大(da)化)和(he)(he)在建電站(zhan)(平班(ban)、龍(long)灘)及沿岸國家和(he)(he)人(ren)民生命財產(chan)關系重大(da),若(ruo)出現意(yi)外,將是災難性的,損失難以估量,所以必須(xu)保證大(da)壩(ba)的安(an)全(quan)運行。
(2)一(yi)(yi)級(ji)(ji)(ji)電(dian)(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan)(zhan)下(xia)游6.5km為天生橋(qiao)二(er)級(ji)(ji)(ji)水電(dian)(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan)(zhan)首部樞紐(niu)。二(er)級(ji)(ji)(ji)電(dian)(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan)(zhan)為逕流(liu)式電(dian)(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan)(zhan),水庫(ku)有效庫(ku)容(rong)僅為800萬m3,無調節性(xing)能。二(er)級(ji)(ji)(ji)電(dian)(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan)(zhan)溢流(liu)壩閘門為平板門,單寬流(liu)量(liang)小,一(yi)(yi)級(ji)(ji)(ji)電(dian)(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan)(zhan)溢洪(hong)道閘門為弧(hu)形門,單寬流(liu)量(liang)大(da),所(suo)以天生橋(qiao)一(yi)(yi)、二(er)級(ji)(ji)(ji)電(dian)(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan)(zhan)的(de)(de)(de)聯(lian)合(he)(he)渡汛將(jiang)(jiang)十分重要(yao)。一(yi)(yi)、二(er)級(ji)(ji)(ji)電(dian)(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan)(zhan)泄洪(hong)時(shi)要(yao)密(mi)切配合(he)(he),一(yi)(yi)級(ji)(ji)(ji)電(dian)(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan)(zhan)每開(kai)一(yi)(yi)扇閘門要(yao)等二(er)級(ji)(ji)(ji)電(dian)(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan)(zhan)達到相(xiang)近(jin)的(de)(de)(de)泄流(liu)量(liang),穩定安(an)全運(yun)行的(de)(de)(de)水位,一(yi)(yi)級(ji)(ji)(ji)電(dian)(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan)(zhan)才(cai)能開(kai)一(yi)(yi)下(xia)扇閘門,以此(ci)類推。當泄流(liu)量(liang)較(jiao)(jiao)大(da)時(shi),閘門操(cao)作時(shi)間較(jiao)(jiao)長,并且整個(ge)閘門操(cao)作過程一(yi)(yi)、二(er)級(ji)(ji)(ji)要(yao)配合(he)(he)好(hao),不能出現調度、聯(lian)系、操(cao)作等每個(ge)環節的(de)(de)(de)錯誤,否則將(jiang)(jiang)對二(er)級(ji)(ji)(ji)電(dian)(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan)(zhan)的(de)(de)(de)安(an)全帶來較(jiao)(jiao)大(da)影(ying)響。
(3)一(yi)級電站大(da)壩(ba)的(de)(de)(de)(de)安全(quan)運行,關鍵在面(mian)(mian)板(ban)(ban)(ban)(ban)(ban)(ban)、面(mian)(mian)板(ban)(ban)(ban)(ban)(ban)(ban)與(yu)趾(zhi)板(ban)(ban)(ban)(ban)(ban)(ban)之(zhi)間的(de)(de)(de)(de)周邊縫的(de)(de)(de)(de)工作狀(zhuang)態(tai)(tai)。現代混凝(ning)土(tu)面(mian)(mian)板(ban)(ban)(ban)(ban)(ban)(ban)堆(dui)石壩(ba)設計的(de)(de)(de)(de)原則之(zhi)一(yi)是(shi),面(mian)(mian)板(ban)(ban)(ban)(ban)(ban)(ban)的(de)(de)(de)(de)應力狀(zhuang)態(tai)(tai)直接和(he)堆(dui)石壩(ba)體(ti)(ti)變形(xing)有關,和(he)水(shui)壓力關系不明(ming)顯(xian)。意味著面(mian)(mian)板(ban)(ban)(ban)(ban)(ban)(ban)主(zhu)(zhu)要承受它和(he)堆(dui)石壩(ba)體(ti)(ti)之(zhi)間的(de)(de)(de)(de)位移差(cha)引起的(de)(de)(de)(de)荷載,不主(zhu)(zhu)要承受水(shui)壓力。面(mian)(mian)板(ban)(ban)(ban)(ban)(ban)(ban)狀(zhuang)態(tai)(tai)取決于堆(dui)石壩(ba)體(ti)(ti)的(de)(de)(de)(de)變形(xing)狀(zhuang)態(tai)(tai)。面(mian)(mian)板(ban)(ban)(ban)(ban)(ban)(ban)主(zhu)(zhu)要是(shi)傳遞水(shui)壓力給大(da)壩(ba)堆(dui)石體(ti)(ti),由于面(mian)(mian)板(ban)(ban)(ban)(ban)(ban)(ban)是(shi)鋼(gang)筋混凝(ning)土(tu),屬剛性(xing)體(ti)(ti),受大(da)壩(ba)變形(xing)影響(xiang),面(mian)(mian)板(ban)(ban)(ban)(ban)(ban)(ban)將產生(sheng)裂縫,同時(shi)面(mian)(mian)板(ban)(ban)(ban)(ban)(ban)(ban)與(yu)大(da)壩(ba)墊層料產生(sheng)脫空,也將使面(mian)(mian)板(ban)(ban)(ban)(ban)(ban)(ban)產生(sheng)裂縫,需(xu)及時(shi)做出修補(bu),否則將影響(xiang)大(da)壩(ba)的(de)(de)(de)(de)安全(quan)運行。
(4)溢洪(hong)道是天生橋一(yi)(yi)級水電站唯一(yi)(yi)的泄(xie)洪(hong)設施,它的安(an)全運(yun)行關系到大壩的安(an)全,同時對下游(you)已建工程及(ji)沿河國家及(ji)人(ren)民財產(chan)影響重大,所以對溢洪(hong)道機電設備及(ji)金屬結構的檢查(cha)、維護極為重要,必(bi)須確保每次閘門(men)操作能(neng)正常進(jin)行。
(5)天(tian)生橋一級電(dian)(dian)站(zhan)水(shui)(shui)庫(ku)庫(ku)容大,對(dui)下(xia)游已建(jian)電(dian)(dian)站(zhan)的(de)經(jing)濟(ji)效益顯著,可(ke)增加已建(jian)電(dian)(dian)站(zhan)(天(tian)生橋二(er)級、巖灘、大化(hua))的(de)保證出(chu)(chu)力88.39萬kW,增加年(nian)(nian)發電(dian)(dian)量40.77億(yi)kW.h,相(xiang)當于(yu)新建(jian)一座百萬千瓦級的(de)水(shui)(shui)電(dian)(dian)站(zhan)。一級電(dian)(dian)站(zhan)每年(nian)(nian)汛(xun)(xun)未(wei)的(de)水(shui)(shui)庫(ku)蓄(xu)(xu)(xu)水(shui)(shui)對(dui)電(dian)(dian)站(zhan)群(qun)的(de)經(jing)濟(ji)效益至關重要,設計文件規定(ding),一級電(dian)(dian)站(zhan)水(shui)(shui)庫(ku)汛(xun)(xun)限水(shui)(shui)位(wei)為773.1m,在9月(yue)10日后才(cai)能蓄(xu)(xu)(xu)至正常水(shui)(shui)位(wei)780.0m運行,由于(yu)南盤江流域(yu)主汛(xun)(xun)期為每年(nian)(nian)6~8月(yue),對(dui)水(shui)(shui)庫(ku)蓄(xu)(xu)(xu)水(shui)(shui)帶來不(bu)(bu)利影響,如果出(chu)(chu)現主汛(xun)(xun)期來水(shui)(shui)集中,后汛(xun)(xun)期(9~10月(yue))來水(shui)(shui)較少,就可(ke)能出(chu)(chu)現水(shui)(shui)庫(ku)不(bu)(bu)能蓄(xu)(xu)(xu)水(shui)(shui)至正常水(shui)(shui)位(wei)780.0m運行,所(suo)以(yi)應(ying)對(dui)汛(xun)(xun)限水(shui)(shui)位(wei)773.1m進行調整提(ti)高或對(dui)可(ke)蓄(xu)(xu)(xu)至正常水(shui)(shui)位(wei)的(de)時間(9月(yue)10日)調整,可(ke)以(yi)考(kao)慮對(dui)汛(xun)(xun)限水(shui)(shui)位(wei)進行動(dong)態管理,在滿(man)足(zu)電(dian)(dian)站(zhan)安全運行的(de)前提(ti)下(xia),可(ke)適時根(gen)據每年(nian)(nian)來水(shui)(shui)情況進行調整,有利水(shui)(shui)庫(ku)蓄(xu)(xu)(xu)水(shui)(shui)。
(6)天(tian)生(sheng)橋一級電(dian)站(zhan)放(fang)(fang)空(kong)(kong)洞作(zuo)為(wei)在施工期參(can)加導(dao)流,運(yun)(yun)行(xing)(xing)期作(zuo)為(wei)電(dian)站(zhan)旁通和放(fang)(fang)空(kong)(kong)水庫(ku)(ku)用的特點,放(fang)(fang)空(kong)(kong)洞的安全運(yun)(yun)行(xing)(xing)較重要。由(you)于(yu)放(fang)(fang)空(kong)(kong)洞工作(zuo)閘(zha)門屬于(yu)地下洞室,有滲水,空(kong)(kong)氣流動性差,較潮(chao)(chao)濕,閘(zha)門控制設備容(rong)易(yi)受潮(chao)(chao),不能(neng)保證(zheng)正(zheng)常工作(zuo),需作(zuo)防水、通風處(chu)理,由(you)于(yu)大壩是目前運(yun)(yun)行(xing)(xing)最(zui)高的面板堆石壩,如果大壩出現(xian)險(xian)情,必須(xu)保證(zheng)放(fang)(fang)空(kong)(kong)洞能(neng)及時運(yun)(yun)行(xing)(xing),開閘(zha)放(fang)(fang)水降低(di)庫(ku)(ku)水位,所(suo)以放(fang)(fang)空(kong)(kong)洞的閘(zha)門操作(zuo)系統要維(wei)護好,以保證(zheng)隨時能(neng)投入運(yun)(yun)行(xing)(xing)。
(7)引水系統(tong)跨左(zuo)岸10#沖(chong)溝(gou),由于隧(sui)洞(dong)(dong)(dong)在沖(chong)溝(gou)部位為中(zhong)厚(hou)層(ceng)(ceng)泥巖(yan)(yan)和砂巖(yan)(yan)互(hu)層(ceng)(ceng),局部上覆巖(yan)(yan)體(ti)較薄,最薄處(chu)只有21.4m,在該段的(de)隧(sui)洞(dong)(dong)(dong)采用(yong)后(hou)張控預應力錨索技術,隧(sui)洞(dong)(dong)(dong)投入(ru)運行(xing)測(ce)(ce)壓管水位在蓄水后(hou)有明(ming)顯升高,宜控制滲(shen)壓防(fang)止(zhi)發生(sheng)水力劈(pi)裂(lie),2000年在10#沖(chong)溝(gou)隧(sui)洞(dong)(dong)(dong)上履巖(yan)(yan)進(jin)行(xing)灌漿(jiang)處(chu)理,以提(ti)高圍巖(yan)(yan)的(de)彈性模(mo)量。經過灌漿(jiang)圍巖(yan)(yan)彈性模(mo)量得到明(ming)顯提(ti)高。同時(shi)利用(yong)68#地質探(tan)洞(dong)(dong)(dong)(在10#沖(chong)溝(gou)上游側(ce))補(bu)打排水孔,降(jiang)低巖(yan)(yan)體(ti)滲(shen)透壓力,經過觀測(ce)(ce),測(ce)(ce)壓管水位得到降(jiang)低,有效防(fang)止(zhi)水力劈(pi)裂(lie)的(de)產生(sheng),提(ti)高了隧(sui)洞(dong)(dong)(dong)的(de)安全運行(xing)。