某水庫(kù)除險(xiǎn)加固工程的溢洪道除險(xiǎn)加固計(jì)算案例1.1溢洪道現(xiàn)狀該水庫(kù)的溢洪道是水庫(kù)剛開始修建的時(shí)期一起修建的，該溢洪道的類型屬于武閘門的寬頂堰，現(xiàn)在的基本情況是堰頂高程19.20m，堰寬5.9m，坎高1.09m，在控制段曾經(jīng)修建有一座交通橋不過現(xiàn)在已經(jīng)倒掉了，已經(jīng)不能正常使用了。對(duì)溢洪道的管理和使用造成了極大的麻煩。泄槽段是直接開挖的土渠由于多年的使用其已經(jīng)不能承擔(dān)原有的泄流任務(wù)了，現(xiàn)在土渠堵塞極為嚴(yán)重由于淤積的污物沒有及時(shí)處理，而且在有的段土體倒塌嚴(yán)重影響泄洪對(duì)下游安全造成了極大的隱患。而且在溢洪道出口地方?jīng)]有設(shè)置消力池。1.2除險(xiǎn)加固設(shè)計(jì)1.2.1設(shè)計(jì)方案根據(jù)溢洪道目前存在的情況，本次加固包括以下內(nèi)容：1、重建2m長(zhǎng)，底板為400mm厚的C20素混凝土進(jìn)口段；2、拆除緊鄰進(jìn)口段與控制段處的涵管，并清除底部淤積雜物達(dá)到相關(guān)規(guī)范要求，新建開敞式寬頂堰，堰頂高程18.00m，堰寬和堰厚均為6m，底板結(jié)構(gòu)為400mm厚C25鋼筋混凝土，下墊100mm厚C10素砼墊層；控制段頂部新建便橋一座，橋?qū)?.5m，凈跨6.0m用于連接兩側(cè)道路，并在兩側(cè)新建C25砼擋墻及C25鋼筋砼橋臺(tái)；3、堰后接170m長(zhǎng)泄槽，坡比1:100，每10m設(shè)一沉降縫，以三油二氈填縫，底板為300mm厚C25鋼筋混凝土，下墊100mm厚C10素砼墊層，邊墻采用M7.5漿砌石；4、新設(shè)消能防沖設(shè)施，采用底流消能的方式，新建9.4m長(zhǎng)，400mm厚C25鋼筋混凝土消力池，池深0.5m，并新建7m長(zhǎng)M7.5漿砌石海漫，將消能后的水流與后面渠道平順銜接，邊墻采用M7.5漿砌石；溢洪道采用開敞式寬頂堰，凈寬6.0m，設(shè)計(jì)堰頂高程18.00m，加固后全長(zhǎng)194.4m，其中進(jìn)口段2m，控制段6m，泄槽段170m，消力池長(zhǎng)9.4m，池深0.5m，后接7m長(zhǎng)漿砌石海漫，邊墻采用M7.5漿砌石。1.2.2設(shè)計(jì)計(jì)算一、溢洪道水面線計(jì)算溢洪道水面線主要計(jì)算50年一遇校核洪水工況下的水面線，相應(yīng)庫(kù)水位為18.53m，最大下泄流量為3.28m3/s。1.2.3流態(tài)判別根據(jù)《溢洪道設(shè)計(jì)規(guī)范》(SL253-2018)，臨界底坡ik按下式計(jì)算：式中：q－單寬流量，m3/(s.m)；－動(dòng)能修正系數(shù)，可近似的取1.05；g－重力加速度，m/s2；Rk－相應(yīng)臨界水深的水力半徑，m；hk－臨界水深，m；n－糙率，取n=0.020。Ck－謝才系數(shù)（m0.5/s）ik－臨界底坡。根據(jù)選定的參數(shù)和計(jì)算方法，得出相關(guān)數(shù)值如下：q=hRCi由上計(jì)算結(jié)果可知，溢洪道底坡均大于臨界底坡，因此溢洪道均為陡坡，水流形態(tài)均為急流，即加僻水庫(kù)溢洪道宣泄50年一遇校核洪水時(shí)，溢洪道內(nèi)水流形態(tài)均為急流。1.2.4水面線計(jì)算（1）、基本資料高程：根據(jù)測(cè)量資料采用黃海高程系統(tǒng)。斷面：溢洪道除險(xiǎn)加固后，樁號(hào)0+000～0+002段為進(jìn)口水平段，樁號(hào)0+000～0+008為控制段水位近似于庫(kù)水位相同；樁號(hào)0+178～0+194.4段為消力池及海漫。因此，本次僅計(jì)算樁號(hào)0+002～0+178段水面線即可，共取9個(gè)計(jì)算斷面，樁號(hào)從上游至下游依次為0+002、0+021、0+040、0+59、0+78、0+098、0+118、0+138、0+158、0+178。糙率：參考規(guī)范本水庫(kù)溢洪道糙率取0.020。流量：本次溢洪道流量取p=2%校核洪水對(duì)應(yīng)的最大下泄流量，即Q=3.28m3/s。（2）、起推水位取斷面樁號(hào)0+002處為起始計(jì)算斷面，本次設(shè)計(jì)近似取起始計(jì)算斷面處水深為臨界水深hk=0.31m，則起推水位為Z0=18.00+0.31=18.31m。（3）、計(jì)算方法①根據(jù)《溢洪道設(shè)計(jì)規(guī)范》，按陡槽段水面線采用下式進(jìn)行計(jì)算：式中：—分段長(zhǎng)度；h1、h2—分段始、末斷面水深；v1、v2—分段始、末斷面平均流速；α1、α2—流速分布不均勻系數(shù)取1.05；θ—泄槽底坡角度；i—泄槽底坡為0.01；—分段內(nèi)平均摩阻坡降；n—泄槽槽身糙率系數(shù)；—分段平均流速，=(v1+v2)／2；—分段平均水力半徑，=(R1+R2)／2。當(dāng)溢洪道水流滿足條件Fr>2時(shí)，按照《溢洪道設(shè)計(jì)規(guī)范》（SL253—2018）應(yīng)考慮水流摻氣的影響，摻氣水深按下式計(jì)算：式中：h—泄槽計(jì)算斷面的水深；hb—泄槽計(jì)算斷面摻氣后的水深；v—不摻氣情況下泄槽計(jì)算面的流速，m／s；ζ—修正系數(shù)，取1.4。6.4計(jì)算結(jié)果根據(jù)選定的參數(shù)和計(jì)算方法，計(jì)算得出加僻水庫(kù)宣泄設(shè)計(jì)洪水時(shí)，溢洪道水面線成果見表斷面h

(m)b

(m)m1m2A

(m2)Pω

(m)R

(m)R1/6

(m)nC

(m)(1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)10.31000000006001.86006.6200.2810.8090.0221.44920.27810000006001.66866.5560.2550.7960.0220.080330.27510000006001.65066.5500.2520.7950.0219.947840.27450000006001.64706.5490.2510.7940.0219.921250.27445500006001.64676.5490.2510.7940.0219.919260.27444800006001.64676.5490.2510.7940.0219.918970.27444700006001.64676.5490.2510.7940.0219.918980.27444686006001.64676.5490.2510.7940.0219.918990.27444684006001.64676.5490.2510.7940.0219.9189100.27444683686001.64676.5490.2510.7940.0219.9189ν

(m/s)αν2

2g

(m)J均i-J均△s

(m)∑△s

(m)里程

（m）(12)(13)(19)(20)(21)(22)(23)61.7630.1660+221.9660.2070.008070.0019320.75020.7500+2121191.9870.2110.009750.0002518.17538.9260+4040191.9910.2120.009960.0000422.24161.1670+5959191.9920.2120.010000.0000019.21980.3860+7878191.9920.2120.010000.0000019.658100.0440+9898201.9920.2120.010000.0000019.736119.7800+118118201.9920.2120.010000.0000019.592139.3720+138138201.9920.2120.010000.0000019.277158.6490+158158201.9920.2120.010000.0000021.080179.7290+17817820摻氣后水深（m）安全超高（m）邊墻高H

（m）水位邊墻高程0.3180.5000.81818.31818.8180.2860.5000.78618.0647518.564750.2830.5000.78317.7387518.238750.2820.5000.78217.4151517.915150.2820.5000.78217.0921117.592110.2820.5000.78216.752117.25210.2820.5000.78216.412116.91210.2820.5000.78216.072116.57210.2820.5000.78215.732116.23210.2820.5000.78215.392115.8921根據(jù)選定的參數(shù)和計(jì)算方法，計(jì)算得出加僻水庫(kù)宣泄校核洪水時(shí)，溢洪道水面線成果見表斷面h

(m)b

(m)m1m2A

(m2)Pω

(m)R

(m)R1/6

(m)nC

(m)(1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)10.45000000006002.70006.9000.3910.8550.0226.749320.37590000006002.25546.7520.3340.8330.0224.071730.36150000006002.16906.7230.3230.8280.0223.519840.35745000006002.14476.7150.3190.8270.0223.362650.35619000006002.13716.7120.3180.8260.0223.313560.35579000006002.13476.7120.3180.8260.0223.297970.35568200006002.13416.7110.3180.8260.0223.293780.35564650006002.13396.7110.3180.8260.0223.292390.35563650006002.13386.7110.3180.8260.0223.2919100.35563450006002.13386.7110.3180.8260.0223.2918ν

(m/s)αν2

2g

(m)J均i-J均△s

(m)∑△s

(m)里程

（m）(12)(13)(19)(20)(21)(22)(23)61.8410.1810+222.2040.2600.006350.0036521.29221.2920+2121192.2910.2810.008920.0010819.44640.7380+4040192.3170.2870.009660.0003418.92059.6580+5959192.3260.2890.009890.0001119.15378.8110+7878192.3280.2900.009970.0000320.25999.0700+9898202.3290.2900.009990.0000119.002118.0720+118118202.3290.2900.010000.0000020.712138.7840+138138202.3290.2900.010000.0000021.950160.7340+158158202.3290.2900.010000.0000016.166176.9000+17817820摻氣后水深（m）安全超高（m）邊墻高H

（m）水位邊墻高程0.4620.5000.96218.31818.8180.3870.5000.88718.166518.66650.3730.5000.87317.829118.32910.3690.5000.86917.5020518.002050.3680.5000.86817.1777917.677790.3670.5000.86716.8373917.337390.3670.5000.86716.4972816.997280.3670.5000.86716.1572416.657240.3670.5000.86715.8172316.317230.3670.5000.86715.4772315.97723由以上計(jì)算結(jié)果可知，本次除險(xiǎn)加固溢洪道側(cè)墻設(shè)計(jì)高程滿足要求，故溢洪道設(shè)計(jì)方案合理。1.3消能計(jì)算本次加固設(shè)計(jì)消能工采用底流式消能防沖，根據(jù)《溢洪道設(shè)計(jì)規(guī)范》，建筑物消能防沖型式采用下挖式消力池，按50年一遇設(shè)計(jì)，P=2%洪水對(duì)應(yīng)的最大下泄流量為4.97m3/s，上游庫(kù)水位為18.53m。1、自由水躍躍后共軛水深h2按下式計(jì)算：式中：