天生(sheng)橋一級水(shui)(shui)電(dian)(dian)(dian)站為西(xi)電(dian)(dian)(dian)東送的(de)重點(dian)工程(cheng),也是(shi)珠江(jiang)流域西(xi)江(jiang)水(shui)(shui)系上游的(de)南盤江(jiang)龍(long)頭電(dian)(dian)(dian)站,電(dian)(dian)(dian)站總裝(zhuang)機(ji)容(rong)量為1200MW(4×300MW),電(dian)(dian)(dian)站于1998年底首(shou)臺機(ji)組發電(dian)(dian)(dian),至(zhi)2000年工程(cheng)竣工。
工程特征
溢洪(hong)(hong)(hong)道(dao)布置于右岸埡口處,其開挖料為(wei)(wei)(wei)大壩填筑(zhu)的主(zhu)要(yao)料源。溢洪(hong)(hong)(hong)道(dao)設(she)計標準為(wei)(wei)(wei)千年一(yi)遇洪(hong)(hong)(hong)水(Q=20900m3/s)設(she)計,可能最大洪(hong)(hong)(hong)水(Q=28500m3/s)校核。經水庫調(diao)洪(hong)(hong)(hong)后,相應的下泄(xie)流(liu)量分別為(wei)(wei)(wei)14782m3/s和21750m3/s。泄(xie)洪(hong)(hong)(hong)孔(kong)口尺寸為(wei)(wei)(wei)寬13m,高20m,共(gong)5孔(kong)。
溢洪(hong)道(dao)(dao)全長1665m,由引(yin)(yin)(yin)渠(qu)(qu)、溢流堰(yan)、泄(xie)槽(cao)(cao)(cao)(cao)、挑(tiao)流鼻坎和(he)護(hu)岸工程組(zu)成。引(yin)(yin)(yin)渠(qu)(qu)長1122m,底(di)(di)寬120m,渠(qu)(qu)底(di)(di)高(gao)程745m,底(di)(di)坡i=0。渠(qu)(qu)道(dao)(dao)兩側為(wei)(wei)垂直(zhi)邊坡,每隔(ge)(ge)22m高(gao)設1條(tiao)12m寬的(de)馬(ma)道(dao)(dao),引(yin)(yin)(yin)渠(qu)(qu)基本(ben)不襯砌。溢流堰(yan)頂高(gao)程760m,設5孔寬13m高(gao)20m的(de)弧形閘門,溢流前緣總(zong)長81m。堰(yan)后(hou)為(wei)(wei)泄(xie)槽(cao)(cao)(cao)(cao),泄(xie)槽(cao)(cao)(cao)(cao)平面采用(yong)不對稱收縮體型(xing),橫斷(duan)面為(wei)(wei)矩形,縱坡i=13%。為(wei)(wei)避免氣(qi)蝕破壞,在(zai)泄(xie)槽(cao)(cao)(cao)(cao)段共(gong)設5道(dao)(dao)摻氣(qi)槽(cao)(cao)(cao)(cao)。泄(xie)槽(cao)(cao)(cao)(cao)軸線與下游河(he)道(dao)(dao)的(de)交(jiao)角(jiao)為(wei)(wei)50°~60°,且流速(su)高(gao),泄(xie)量大,泄(xie)洪(hong)功率(lv)達2800萬kW。經(jing)水(shui)力模(mo)型(xing)試驗研究,選用(yong)左槽(cao)(cao)(cao)(cao)正向擴(kuo)散連(lian)續大挑(tiao)角(jiao)鼻坎和(he)右槽(cao)(cao)(cao)(cao)窄縫曲(qu)面貼角(jiao)斜鼻坎的(de)結(jie)合方案,較好地(di)解決了泄(xie)流消(xiao)能問題。在(zai)工程建(jian)設過程中,對上(shang)述設計方案做了簡(jian)化,取消(xiao)了泄(xie)槽(cao)(cao)(cao)(cao)中隔(ge)(ge)墩;又經(jing)水(shui)力模(mo)型(xing)試驗,選取了兩側擴(kuo)散的(de)舌形鼻坎方案,在(zai)出口河(he)岸相應(ying)地(di)做了保護(hu)。
引水發電系統
引(yin)水發電系統位(wei)于左(zuo)岸(an)砂泥(ni)巖(yan)地區。進水口(kou)設(she)在左(zuo)岸(an)8號(hao)沖溝內,10號(hao)沖溝下游(you)側布置地面廠房,采用單(dan)機單(dan)管布置。
引水(shui)(shui)系(xi)統包(bao)括(kuo)引渠(qu)、進水(shui)(shui)口、引水(shui)(shui)隧洞和(he)(he)壓(ya)力鋼(gang)管(guan)(guan)道。根據進水(shui)(shui)口的布(bu)置(zhi),傍山(shan)開挖形(xing)(xing)成(cheng)引渠(qu)。引渠(qu)沿中(zhong)心(xin)線長(chang)度為284m,梯形(xing)(xing)復式斷面。其底板寬98m,高程710m。進水(shui)(shui)口采用(yong)岸邊塔式,進水(shui)(shui)塔長(chang)98m,寬27.5m,高84m。設(she)置(zhi)2道直柵(zha)槽,內設(she)16扇攔污柵(zha),1扇檢修門(men)及4扇事故門(men)。對(dui)外通(tong)過塔頂交通(tong)橋(qiao)與左(zuo)岸公(gong)路相連。引水(shui)(shui)隧洞4條(tiao),中(zhong)心(xin)距(ju)24m,內徑(jing)(jing)9.6m,縱坡7.5%~10%,水(shui)(shui)平投(tou)影長(chang)380.39~494.09m。結構設(she)計采用(yong)一(yi)次支護和(he)(he)二次襯砌(qi)形(xing)(xing)式,局部過溝地段(duan)二次支護改用(yong)后張法預應力混凝(ning)土襯砌(qi)。壓(ya)力鋼(gang)管(guan)(guan)道4條(tiao),中(zhong)心(xin)距(ju)23.1m,采用(yong)斜井布(bu)置(zhi),坡度50°,由上彎(wan)管(guan)(guan)、斜井管(guan)(guan)、下彎(wan)管(guan)(guan)和(he)(he)水(shui)(shui)平管(guan)(guan)組成(cheng)。鋼(gang)管(guan)(guan)內徑(jing)(jing)7~8.2m,水(shui)(shui)平投(tou)影長(chang)158.78~172.19m,管(guan)(guan)壁厚22~30mm。
地面廠房
地面(mian)廠房位于左岸(an)10號沖溝(gou)下游側,順河(he)向(xiang)(xiang)布置。廠區后山坡(po)臨時邊(bian)坡(po)高(gao)達154m,永久邊(bian)坡(po)高(gao)達109m,并(bing)(bing)有斷層和向(xiang)(xiang)背斜結構(gou)面(mian),對邊(bian)坡(po)穩定有影(ying)響。為此做了(le)(le)(le)大量邊(bian)坡(po)穩定分析,采取了(le)(le)(le)邊(bian)坡(po)綜合(he)治理(li)措施,并(bing)(bing)設(she)置了(le)(le)(le)監測系統。
主(zhu)廠(chang)房(fang)長154.4m,寬(kuan)26m,高(gao)67m。廠(chang)房(fang)內(nei)安裝4臺單機(ji)容量為(wei)300MW的(de)水(shui)輪發電(dian)機(ji)組,其安裝高(gao)程(cheng)為(wei)633.5m。上(shang)(shang)游側副廠(chang)房(fang)布(bu)置電(dian)氣設(she)備(bei)(bei),下(xia)游側副廠(chang)房(fang)布(bu)置水(shui)輪機(ji)設(she)備(bei)(bei),端頭(tou)副廠(chang)房(fang)為(wei)中(zhong)控(kong)室及計算機(ji)監控(kong)設(she)備(bei)(bei)。主(zhu)變壓器布(bu)置在上(shang)(shang)游側副廠(chang)房(fang)的(de)上(shang)(shang)游,出線架位于上(shang)(shang)游副廠(chang)房(fang)屋(wu)頂上(shang)(shang),4回(hui)220kV出線至(zhi)換流站。
放空隧洞
放(fang)空(kong)隧(sui)(sui)洞(dong)(dong)位(wei)于(yu)右(you)岸1號沖溝的(de)下游側(ce),全長(chang)1062.17m,進口高程為(wei)660m,具有施工(gong)期參(can)與(yu)后(hou)期導(dao)流(liu)(liu)、水(shui)(shui)庫蓄水(shui)(shui)期向下游電站供水(shui)(shui)、運(yun)行(xing)期放(fang)空(kong)水(shui)(shui)庫檢(jian)修大(da)壩面板(ban)等功能。距(ju)放(fang)空(kong)隧(sui)(sui)洞(dong)(dong)進口339.17m處(chu)(chu)設(she)事(shi)故(gu)閘門(men)(men)并(bing),并(bing)高131m,內(nei)徑(jing)11.4m,內(nei)設(she)6.8m×9m的(de)事(shi)故(gu)平(ping)板(ban)鏈輪閘門(men)(men);距(ju)進口560.67m處(chu)(chu)為(wei)工(gong)作(zuo)閘門(men)(men)室(shi),內(nei)設(she)6.4m×7.5m的(de)工(gong)作(zuo)弧形閘門(men)(men);工(gong)作(zuo)閘門(men)(men)室(shi)之前為(wei)圓(yuan)形有壓隧(sui)(sui)洞(dong)(dong),長(chang)557.67m。內(nei)徑(jing)9.6m;其后(hou)為(wei)方圓(yuan)形無壓隧(sui)(sui)洞(dong)(dong),長(chang)489.5m,寬(kuan)8m,高11m;洞(dong)(dong)后(hou)接長(chang)約(yue)162m的(de)出口明渠及挑流(liu)(liu)鼻坎。
事故閘門井以(yi)交通(tong)便橋(qiao)與右壩頭相接;工(gong)作閘門室以(yi)交通(tong)通(tong)風洞(dong)與場內公路(lu)相連。交通(tong)通(tong)風洞(dong)布置在放空洞(dong)的左側,為雙層結構,上層交通(tong),下層通(tong)風。
大壩安全監測
變形(xing)監測 3.1.1內部變形(xing)監測
變形監測
(l)觀(guan)測(ce)點布(bu)置大壩布(bu)置有3個觀(guan)測(ce)斷(duan)面(mian),0+630斷(duan)面(mian)為(wei)河床(chuang)中部最大斷(duan)面(mian),右(you)岸(an)0十438斷(duan)面(mian)在(zai)1/2壩高處,左岸(an)0十918斷(duan)面(mian)位于地(di)形(xing)突(tu)變部位。在(zai)觀(guan)測(ce)斷(duan)面(mian)的(de)665、692、725、758m高程,共(gong)布(bu)置有沉降(jiang)測(ce)點50個,水平位移測(ce)點31個。
(2)觀測儀器壩體內部垂直位移觀測采用水(shui)管(guan)(guan)式沉(chen)降儀,水(shui)平(ping)(ping)位移觀測采用引張線(xian)式水(shui)平(ping)(ping)位移計。天生橋大壩安裝的垂直、水(shui)平(ping)(ping)位移計管(guan)(guan)線(xian)最大長度達350m,堪稱世界第一。
3.1.2面板撓度監測
面(mian)(mian)(mian)(mian)板撓(nao)(nao)(nao)度(du)(du)觀(guan)(guan)測(ce)(ce)通常采(cai)用埋(mai)設測(ce)(ce)斜(xie)儀(yi)導管的(de)方(fang)法,用活動(dong)式測(ce)(ce)斜(xie)儀(yi)觀(guan)(guan)測(ce)(ce)導管的(de)撓(nao)(nao)(nao)度(du)(du)變形。大(da)(da)壩(ba)(ba)面(mian)(mian)(mian)(mian)板坡(po)長(chang)305m,如采(cai)用活動(dong)式測(ce)(ce)斜(xie)儀(yi)則存在以下(xia)(xia)問(wen)題:測(ce)(ce)繩太(tai)長(chang)可能(neng)產生測(ce)(ce)頭下(xia)(xia)放困難(nan);采(cai)用測(ce)(ce)頭下(xia)(xia)放的(de)輔助牽引裝(zhuang)置(zhi),又耽(dan)心輔助牽引裝(zhuang)置(zhi)一旦發(fa)生故障,很難(nan)檢修;觀(guan)(guan)測(ce)(ce)耗(hao)費(fei)時間很長(chang),也(ye)難(nan)以實(shi)現(xian)觀(guan)(guan)測(ce)(ce)的(de)自動(dong)化等。承建(jian)(jian)(jian)單位的(de)巴西專家,根據辛戈壩(ba)(ba)的(de)經驗,建(jian)(jian)(jian)議(yi)采(cai)用電平器(qi)(qi)(qi)進行面(mian)(mian)(mian)(mian)板撓(nao)(nao)(nao)度(du)(du)觀(guan)(guan)測(ce)(ce),經參建(jian)(jian)(jian)各(ge)方(fang)認真(zhen)研究,這一建(jian)(jian)(jian)議(yi)得(de)到了采(cai)納。電平器(qi)(qi)(qi)是一種固定式測(ce)(ce)斜(xie)儀(yi),觀(guan)(guan)測(ce)(ce)精度(du)(du)高,根據電平器(qi)(qi)(qi)觀(guan)(guan)測(ce)(ce)的(de)測(ce)(ce)點傾角變化可計算面(mian)(mian)(mian)(mian)板的(de)撓(nao)(nao)(nao)度(du)(du)曲線。天生橋大(da)(da)壩(ba)(ba)3個(ge)觀(guan)(guan)測(ce)(ce)斷面(mian)(mian)(mian)(mian)的(de)面(mian)(mian)(mian)(mian)板上游(you)共布置(zhi)64個(ge)電平器(qi)(qi)(qi)來觀(guan)(guan)測(ce)(ce)面(mian)(mian)(mian)(mian)板撓(nao)(nao)(nao)度(du)(du)變形。
3.1.3接縫監(jian)測
(1)周邊縫沿周邊縫布置有12組三向測縫計,觀(guan)測縫面開度(du)、沉降和切向位(wei)移相(xiang)對變化(hua)。
(2)垂(chui)直縫(feng)(feng)在(zai)面(mian)板(ban)垂(chui)直伸(shen)縮縫(feng)(feng)的張(zhang)性(xing)縫(feng)(feng)區、張(zhang)性(xing)縫(feng)(feng)和壓性(xing)縫(feng)(feng)過渡(du)區,跨縫(feng)(feng)布置單向測(ce)(ce)縫(feng)(feng)計24支,用來觀測(ce)(ce)縫(feng)(feng)面(mian)開合變化(hua)。
(3)面(mian)板(ban)脫空(kong)觀(guan)測(ce)(ce)大(da)壩(ba)一期面(mian)板(ban)澆筑后,檢(jian)查發現面(mian)板(ban)頂部與墊層料間有(you)大(da)面(mian)積脫空(kong),決定在(zai)二(er)期面(mian)板(ban)布(bu)(bu)置2組二(er)向測(ce)(ce)縫(feng)計,觀(guan)測(ce)(ce)面(mian)板(ban)和(he)墊層料接觸縫(feng)面(mian)的法(fa)向和(he)切向變形;在(zai)三期面(mian)板(ban)布(bu)(bu)置7組觀(guan)測(ce)(ce)面(mian)板(ban)脫空(kong)變形的二(er)向測(ce)(ce)縫(feng)計。
3.1.4表面(mian)變形(xing)監(jian)測(ce)
在(zai)壩體上、下游壩面和壩頂,共(gong)布(bu)置視準(zhun)線(xian)8條(tiao),其中布(bu)置在(zai)一、二(er)期面板(ban)頂部的視準(zhun)線(xian)為施工期臨時測(ce)線(xian),水平位移觀(guan)測(ce)采用視準(zhun)線(xian)法,垂直位移用水準(zhun)儀觀(guan)測(ce)。
滲流監(jian)測(ce) 3.2.1滲流壓(ya)力監(jian)測(ce)
滲流監測
(1)壩體(ti)滲(shen)流壓力在距(ju)趾板“X”線下游3m的墊層料(liao)區基礎(chu)面,布置有坑埋式滲(shen)壓計(ji)13支,用(yong)來觀測(ce)周邊(bian)縫后壩體(ti)的滲(shen)壓。
(2)壩基滲流壓力在趾板灌(guan)漿(jiang)帷(wei)幕前后(hou),布置(zhi)有鉆孔式滲壓計21支(zhi),觀測壩基滲壓,了(le)解帷(wei)幕阻滲效果(guo)。
(3)繞(rao)壩滲流水位在左(zuo)、右岸壩肩,共(gong)布置16個鉆孔測壓管(guan)觀測繞(rao)壩滲流水位。
3.2.2滲流量監測(ce)
大壩(ba)(ba)(ba)下游布置了1個滲流(liu)匯集(ji)系統。在下游壩(ba)(ba)(ba)腳設置1道截(jie)水墻,攔(lan)截(jie)壩(ba)(ba)(ba)體滲水,使滲流(liu)匯集(ji),通過(guo)布置在右岸的(de)引渠流(liu)向(xiang)下游,在引渠設置量水堰觀(guan)測壩(ba)(ba)(ba)體滲流(liu)。在右岸壩(ba)(ba)(ba)肩(jian)排水系統的(de)2個洞口布置了觀(guan)測壩(ba)(ba)(ba)肩(jian)滲流(liu)量的(de)量水堰。
壓力、應力和溫度監測(ce)(ce) 3.3.1壓力監測(ce)(ce)
壓力應力溫度
大(da)壩0十(shi)630斷面4個不(bu)同高程的面板與墊層料接觸面,布置有觀測(ce)接觸土壓(ya)力(li)(li)(li)的土壓(ya)力(li)(li)(li)計(ji);在壩體過(guo)渡料中(zhong)部和壩軸線處(chu),布置有觀測(ce)平面應力(li)(li)(li)變化的土壓(ya)力(li)(li)(li)計(ji)。大(da)壩共布置土壓(ya)力(li)(li)(li)計(ji)28支。
3.3.2混凝土(tu)面(mian)板應力和溫度監(jian)測(ce)
大壩面板布置了應(ying)力應(ying)變(bian)觀(guan)測(ce)剖面6個,溫度觀(guan)測(ce)剖面4個,有應(ying)變(bian)計(ji)84支(zhi)、無應(ying)力計(ji)15支(zhi)、鋼筋(jin)計(ji)55支(zhi)、溫度計(ji)27支(zhi),共計(ji)181支(zhi)儀器,用來觀(guan)測(ce)面板的應(ying)力、應(ying)變(bian)和溫度變(bian)化。
3.4地(di)震反應監測
大壩(ba)(ba)設置(zhi)了(le)遙(yao)測微震臺(tai)網,記錄壩(ba)(ba)區和庫(ku)區地震情(qing)況(kuang);在(zai)壩(ba)(ba)體(ti)和基巖布置(zhi)強震儀監測壩(ba)(ba)體(ti)的地震反應(ying)。
運行概況
1998年8月天(tian)生橋一級(ji)(ji)電(dian)站水庫正式蓄水,同(tong)年最高(gao)水位達740.36m,發生時(shi)間為(wei)1998年11月8日,1998年12月一級(ji)(ji)電(dian)站首4#機(ji)組(zu)投產發電(dian),此(ci)時(shi)大壩已完成堆石體填(tian)筑(zhu)(787.3m)及三(san)期面(mian)板(ban)澆筑(zhu),下(xia)游壩體經濟斷面(mian)于12月填(tian)筑(zhu)到787.3m高(gao)程。
1999年(nian)水庫最高水位767.19m,為99年(nian)9月1日,大壩進(jin)行(xing)防浪(lang)墻(qiang)及壩體787.3m~791.0m高程施工,99年(nian)12月3#機投入運行(xing)。
2000年(nian)水(shui)庫蓄水(shui)至正(zheng)常水(shui)位780.0m運(yun)行(xing)(10月17日(ri)),年(nian)底大壩施(shi)工(gong)全(quan)部完(wan)成,2000年(nian)9月2#機(ji)投(tou)入(ru)運(yun)行(xing),12月1#機(ji)投(tou)入(ru)運(yun)行(xing),至此(ci)四臺(tai)機(ji)組全(quan)部投(tou)入(ru)運(yun)行(xing)。
2001年水庫(ku)蓄(xu)水至正常水位780.0m運行(xing)(11月11日),2002年水庫(ku)蓄(xu)水至776.96m運行(xing)(9月17日)。
運行特點
(1)天生(sheng)(sheng)橋一(yi)級水電(dian)站為南盤江龍(long)頭電(dian)站,庫(ku)容(rong)大,大壩為世界第二、亞州第一(yi)高的面板堆石壩,大壩的安全將(jiang)(jiang)對下游已建電(dian)站(天生(sheng)(sheng)橋二級、巖灘、大化)和在建電(dian)站(平班(ban)、龍(long)灘)及沿岸(an)國家和人民生(sheng)(sheng)命財產關(guan)系重(zhong)大,若出現意外,將(jiang)(jiang)是災難性的,損失難以估量,所以必須保(bao)證大壩的安全運(yun)行。
(2)一(yi)級(ji)(ji)(ji)(ji)電(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan)下游(you)6.5km為天生橋(qiao)二(er)(er)(er)級(ji)(ji)(ji)(ji)水(shui)電(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan)首部樞紐。二(er)(er)(er)級(ji)(ji)(ji)(ji)電(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan)為逕流式(shi)電(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan),水(shui)庫有效庫容僅為800萬(wan)m3,無調節性能(neng)。二(er)(er)(er)級(ji)(ji)(ji)(ji)電(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan)溢流壩閘門(men)(men)為平板門(men)(men),單(dan)寬(kuan)流量小(xiao),一(yi)級(ji)(ji)(ji)(ji)電(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan)溢洪(hong)(hong)道(dao)閘門(men)(men)為弧形門(men)(men),單(dan)寬(kuan)流量大(da),所以(yi)(yi)天生橋(qiao)一(yi)、二(er)(er)(er)級(ji)(ji)(ji)(ji)電(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan)的聯(lian)(lian)合(he)渡汛將十分(fen)重要(yao)(yao)。一(yi)、二(er)(er)(er)級(ji)(ji)(ji)(ji)電(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan)泄洪(hong)(hong)時要(yao)(yao)密切配(pei)合(he),一(yi)級(ji)(ji)(ji)(ji)電(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan)每(mei)開(kai)(kai)一(yi)扇閘門(men)(men)要(yao)(yao)等二(er)(er)(er)級(ji)(ji)(ji)(ji)電(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan)達到相近的泄流量,穩(wen)定安(an)全(quan)運行的水(shui)位,一(yi)級(ji)(ji)(ji)(ji)電(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan)才能(neng)開(kai)(kai)一(yi)下扇閘門(men)(men),以(yi)(yi)此類推。當(dang)泄流量較大(da)時,閘門(men)(men)操(cao)(cao)作時間較長,并且整個閘門(men)(men)操(cao)(cao)作過(guo)程一(yi)、二(er)(er)(er)級(ji)(ji)(ji)(ji)要(yao)(yao)配(pei)合(he)好,不能(neng)出(chu)現(xian)調度、聯(lian)(lian)系、操(cao)(cao)作等每(mei)個環節的錯(cuo)誤,否則將對二(er)(er)(er)級(ji)(ji)(ji)(ji)電(dian)(dian)(dian)站(zhan)(zhan)(zhan)(zhan)的安(an)全(quan)帶(dai)來(lai)較大(da)影響。
(3)一級電站大(da)壩(ba)(ba)的(de)(de)(de)安(an)全運行(xing),關鍵在(zai)面(mian)(mian)(mian)板(ban)(ban)(ban)(ban)、面(mian)(mian)(mian)板(ban)(ban)(ban)(ban)與趾(zhi)板(ban)(ban)(ban)(ban)之間(jian)的(de)(de)(de)周邊縫(feng)的(de)(de)(de)工作狀(zhuang)(zhuang)態。現代(dai)混(hun)凝(ning)(ning)土面(mian)(mian)(mian)板(ban)(ban)(ban)(ban)堆(dui)石(shi)(shi)壩(ba)(ba)設計的(de)(de)(de)原則(ze)之一是(shi),面(mian)(mian)(mian)板(ban)(ban)(ban)(ban)的(de)(de)(de)應力狀(zhuang)(zhuang)態直接和(he)堆(dui)石(shi)(shi)壩(ba)(ba)體(ti)變形(xing)有關,和(he)水壓力關系不(bu)明(ming)顯。意味著面(mian)(mian)(mian)板(ban)(ban)(ban)(ban)主要承受它和(he)堆(dui)石(shi)(shi)壩(ba)(ba)體(ti)之間(jian)的(de)(de)(de)位(wei)移差引起的(de)(de)(de)荷載,不(bu)主要承受水壓力。面(mian)(mian)(mian)板(ban)(ban)(ban)(ban)狀(zhuang)(zhuang)態取決(jue)于(yu)堆(dui)石(shi)(shi)壩(ba)(ba)體(ti)的(de)(de)(de)變形(xing)狀(zhuang)(zhuang)態。面(mian)(mian)(mian)板(ban)(ban)(ban)(ban)主要是(shi)傳遞(di)水壓力給大(da)壩(ba)(ba)堆(dui)石(shi)(shi)體(ti),由于(yu)面(mian)(mian)(mian)板(ban)(ban)(ban)(ban)是(shi)鋼(gang)筋(jin)混(hun)凝(ning)(ning)土,屬剛(gang)性體(ti),受大(da)壩(ba)(ba)變形(xing)影響(xiang),面(mian)(mian)(mian)板(ban)(ban)(ban)(ban)將(jiang)產(chan)生裂(lie)縫(feng),同時面(mian)(mian)(mian)板(ban)(ban)(ban)(ban)與大(da)壩(ba)(ba)墊層(ceng)料(liao)產(chan)生脫空,也將(jiang)使面(mian)(mian)(mian)板(ban)(ban)(ban)(ban)產(chan)生裂(lie)縫(feng),需及時做出修補(bu),否則(ze)將(jiang)影響(xiang)大(da)壩(ba)(ba)的(de)(de)(de)安(an)全運行(xing)。
(4)溢洪(hong)道是天生橋一級水電站唯一的(de)(de)泄洪(hong)設施,它的(de)(de)安全運行(xing)關系到大壩的(de)(de)安全,同時(shi)對下游已(yi)建工程及沿河國(guo)家及人民財產影響重大,所以對溢洪(hong)道機電設備及金屬(shu)結構的(de)(de)檢查、維護極為重要,必(bi)須確保每次閘門操作能正常進行(xing)。
(5)天生橋一(yi)級(ji)電(dian)(dian)(dian)站(zhan)(zhan)(zhan)水(shui)(shui)(shui)(shui)庫(ku)(ku)(ku)庫(ku)(ku)(ku)容大(da),對(dui)(dui)下游已(yi)建(jian)電(dian)(dian)(dian)站(zhan)(zhan)(zhan)的(de)(de)經濟(ji)效益顯(xian)著,可(ke)增加已(yi)建(jian)電(dian)(dian)(dian)站(zhan)(zhan)(zhan)(天生橋二級(ji)、巖灘、大(da)化)的(de)(de)保證出(chu)力(li)88.39萬kW,增加年(nian)發電(dian)(dian)(dian)量40.77億kW.h,相(xiang)當(dang)于(yu)新建(jian)一(yi)座百萬千(qian)瓦級(ji)的(de)(de)水(shui)(shui)(shui)(shui)電(dian)(dian)(dian)站(zhan)(zhan)(zhan)。一(yi)級(ji)電(dian)(dian)(dian)站(zhan)(zhan)(zhan)每(mei)年(nian)汛(xun)(xun)(xun)未(wei)的(de)(de)水(shui)(shui)(shui)(shui)庫(ku)(ku)(ku)蓄(xu)(xu)水(shui)(shui)(shui)(shui)對(dui)(dui)電(dian)(dian)(dian)站(zhan)(zhan)(zhan)群(qun)的(de)(de)經濟(ji)效益至(zhi)關重要,設計(ji)文件規(gui)定,一(yi)級(ji)電(dian)(dian)(dian)站(zhan)(zhan)(zhan)水(shui)(shui)(shui)(shui)庫(ku)(ku)(ku)汛(xun)(xun)(xun)限水(shui)(shui)(shui)(shui)位(wei)為(wei)773.1m,在(zai)9月(yue)10日(ri)后(hou)(hou)才能蓄(xu)(xu)至(zhi)正(zheng)常水(shui)(shui)(shui)(shui)位(wei)780.0m運(yun)行(xing)(xing)(xing),由于(yu)南(nan)盤(pan)江(jiang)流域主汛(xun)(xun)(xun)期為(wei)每(mei)年(nian)6~8月(yue),對(dui)(dui)水(shui)(shui)(shui)(shui)庫(ku)(ku)(ku)蓄(xu)(xu)水(shui)(shui)(shui)(shui)帶來不(bu)利影響,如果出(chu)現主汛(xun)(xun)(xun)期來水(shui)(shui)(shui)(shui)集中,后(hou)(hou)汛(xun)(xun)(xun)期(9~10月(yue))來水(shui)(shui)(shui)(shui)較少(shao),就可(ke)能出(chu)現水(shui)(shui)(shui)(shui)庫(ku)(ku)(ku)不(bu)能蓄(xu)(xu)水(shui)(shui)(shui)(shui)至(zhi)正(zheng)常水(shui)(shui)(shui)(shui)位(wei)780.0m運(yun)行(xing)(xing)(xing),所以應對(dui)(dui)汛(xun)(xun)(xun)限水(shui)(shui)(shui)(shui)位(wei)773.1m進行(xing)(xing)(xing)調(diao)整(zheng)提高或對(dui)(dui)可(ke)蓄(xu)(xu)至(zhi)正(zheng)常水(shui)(shui)(shui)(shui)位(wei)的(de)(de)時間(9月(yue)10日(ri))調(diao)整(zheng),可(ke)以考慮對(dui)(dui)汛(xun)(xun)(xun)限水(shui)(shui)(shui)(shui)位(wei)進行(xing)(xing)(xing)動態(tai)管理,在(zai)滿足電(dian)(dian)(dian)站(zhan)(zhan)(zhan)安(an)全運(yun)行(xing)(xing)(xing)的(de)(de)前提下,可(ke)適時根(gen)據(ju)每(mei)年(nian)來水(shui)(shui)(shui)(shui)情況進行(xing)(xing)(xing)調(diao)整(zheng),有利水(shui)(shui)(shui)(shui)庫(ku)(ku)(ku)蓄(xu)(xu)水(shui)(shui)(shui)(shui)。
(6)天生橋一(yi)級(ji)電站(zhan)放(fang)(fang)(fang)空(kong)洞(dong)(dong)作(zuo)(zuo)為在施工期(qi)參(can)加導流,運(yun)(yun)行(xing)期(qi)作(zuo)(zuo)為電站(zhan)旁通(tong)和(he)放(fang)(fang)(fang)空(kong)水庫(ku)用的特點,放(fang)(fang)(fang)空(kong)洞(dong)(dong)的安(an)全(quan)運(yun)(yun)行(xing)較重要(yao)。由(you)于(yu)放(fang)(fang)(fang)空(kong)洞(dong)(dong)工作(zuo)(zuo)閘門屬于(yu)地下洞(dong)(dong)室,有(you)滲水,空(kong)氣流動性(xing)差,較潮(chao)濕,閘門控制設備(bei)容易受潮(chao),不能保證正(zheng)常工作(zuo)(zuo),需作(zuo)(zuo)防(fang)水、通(tong)風(feng)處(chu)理(li),由(you)于(yu)大壩是目前運(yun)(yun)行(xing)最高(gao)的面板堆石壩,如果大壩出現險情,必須保證放(fang)(fang)(fang)空(kong)洞(dong)(dong)能及時運(yun)(yun)行(xing),開閘放(fang)(fang)(fang)水降低庫(ku)水位(wei),所以放(fang)(fang)(fang)空(kong)洞(dong)(dong)的閘門操(cao)作(zuo)(zuo)系統要(yao)維(wei)護好(hao),以保證隨(sui)時能投(tou)入運(yun)(yun)行(xing)。
(7)引(yin)水系統跨(kua)左岸(an)10#沖溝(gou)(gou),由(you)于隧(sui)洞在(zai)沖溝(gou)(gou)部位為中厚層泥巖和砂巖互層,局部上(shang)覆巖體(ti)較薄(bo),最薄(bo)處只有21.4m,在(zai)該段的隧(sui)洞采用后(hou)張控(kong)預應力錨索技(ji)術,隧(sui)洞投入運行測(ce)壓(ya)(ya)管(guan)(guan)水位在(zai)蓄水后(hou)有明顯升(sheng)高,宜(yi)控(kong)制滲壓(ya)(ya)防止(zhi)發生水力劈(pi)裂,2000年在(zai)10#沖溝(gou)(gou)隧(sui)洞上(shang)履巖進行灌漿(jiang)處理,以提高圍巖的彈(dan)性(xing)模(mo)量。經過(guo)灌漿(jiang)圍巖彈(dan)性(xing)模(mo)量得(de)到(dao)明顯提高。同時利用68#地質探洞(在(zai)10#沖溝(gou)(gou)上(shang)游側(ce))補打排(pai)水孔(kong),降(jiang)低(di)(di)巖體(ti)滲透壓(ya)(ya)力,經過(guo)觀(guan)測(ce),測(ce)壓(ya)(ya)管(guan)(guan)水位得(de)到(dao)降(jiang)低(di)(di),有效防止(zhi)水力劈(pi)裂的產生,提高了隧(sui)洞的安(an)全運行。