鋼板樁圍堰計算單

1、桂林南洲大橋P2主墩鋼板樁圍堰計算單復核 項目負貴 總工程師:中鐵大橋局集團二公司設計部二00五年一月一、概況桂林市南洲大橋位于桂林市疊彩區(qū)大沙鄉(xiāng)境內(nèi)，全長320m.跨徑組合為 (50+87+144+39)m，其中87m和144m為曲塔雙索面斜拉橋，斜拉橋東西兩側(cè)各 接50m輔道孔和39m過渡孔。斜拉橋采用塔梁固接扇形雙索面結(jié)構(gòu)形式，主跨采 用鋼砼疊合梁，邊跨采用預應力砼梁.主墩下設兩個相對獨立的直徑D=21m的圓 形承臺，每個厚度為5m。承臺布置24根615m鉆孔樁和6根備用樁.承臺底標 高+141。0m，頂標高+146.0m，常水位 +146.65m，筑島頂+147。8m。從技術、經(jīng)濟兩方

2、面考慮，P2主墩的承臺施工采用SP-U400型鋼板樁，其 規(guī)格為：寬度 b=400mm，高度 h=1600mm,腹板厚 16.0mm;重量76。1kg/m，每米慣性距34400cm4，每米截面模量2150cm3二、設計計算1、封底厚度(根據(jù)簡明施工計算手冊P339計算) 封底砼采用C20，設封底厚度為h靜水壓力對封底砼形成的荷載p =y (146.65 -141.0 + h) - 24h = 56.5 -14h按簡支雙向板進行計算=6.6m，12 = 6.647m, ll2 = 0.99查表得5 = 0.0429，M = dpi 2M = M = 0.0429 x (56.5 -14h) x

3、6.62 = 105.6 26.16h73.5KMh = ； bf ctK = 2.65， D = 0.35m， b = 1m, f = 1.1N / mm2cth = 1.148m取封底厚度為1.2m?；映镣戤吅箜殭z查坑底各處標高均不大于+1398m,各處封底砼均應保 證1.2m厚。2、各工況鋼板樁埋深及強度計算(根據(jù)深基坑工程設計施工手冊計算)各土層地質(zhì)情況：土層1：天然容重匕=20.5KN/m3,浮容重* = 7.5KN/m3 ,粘聚力氣=0，內(nèi)摩 擦角中 1 = 420, K 1 = tan2（45 ） = 0.2 , K 1 = tan2（45 + * = 5土層 2:天然容重Y

4、2 = 18.3KN/m3，浮容重y 2 = 7.26KN/m3，粘聚力 = 22KPa , 內(nèi)摩擦角中 2 = 8.5。，K 2 = tan2（45 ） = 0.742，K 2 = tan2（45 + #） = 1.347取1米寬鋼板樁進行計算，設圍堰頂有施工荷載q = 39KPa。工況一：鋼板樁插打完，開挖圍堰內(nèi)土體至標高+144。8時（見圖1）確定鋼板樁埋深計算原則：所有外力均對D點取矩，被動土壓力產(chǎn)生的力矩須大于主動土壓力產(chǎn)生的力矩。土壓力計算：主動土壓力：p a = qK 1 = 39 x 0.2 = 7.8 KPap B = (q + y 1 h1)K 1 = (39 + 20.5

5、 x 1.15) x 0.2 = 12.515KPa TOC o 1-5 h z p = (q +y h +yh )K = 39 + 20.5x 1.15 + 7.5 x (h +1.85) x 0.2 = (15.29 + 1.5h )KPa aD1112 a133E = 1(p + p ) x h = - x (7.8 +12.515) x 1.15 = 11.68KN a12aAaB12E = 1(p + p ) x h = 1 x (12.515 +15.29 + 1.5h ) x (1.85 + h ) = (13.9 + 0.75h )(h +1.85)KNa22aBaD22333

6、3被動土壓力：p =y h K = 7.5xh x5 = 37.5h KPa pD 1 3 p133E = 1 p x h = 1 x 37.5h x h = 18.75h2KN p 2 pD 32333水壓力計算：p =y (1.85 + h ) = 18.5 +10h sD w33E1 = 2p D x (h3 +1.85) = 5(h3 +1.85)2p c =y x 1.85 = 18.5E 2 = 2(p c + p D) x h3 = (5h3 + 1.85)h3.h 2 p .h 2 p + px ( x aBaD) + E3PaB + PaDE a1Es2x (h x 2paA

7、 + PaB E a1Es2 TOC o 1-5 h z 3 p + p 2a 2x (奴2)=03p C + p Dx (115 x 2 x 7.8 + 12.515 +1.85 + h ) + (13.9 + 0.75h ) x (h +1.85) x37.8 +12.51531.85 + h 2 x 12.515 + (15.29 + 1.5h )h +1.85(3x 1251511 5h 3 ) + 5(h3 +1.85)2 x-18.75h;.37(5h + 18.5)h x (奴 2x庭 + (18.5 + 10h3) = 033318.5 + (18.5 + 10h3) h =

8、4.1m3鋼板樁入土深度應大于4.1m。鋼板樁強度檢算： 由剪力等于零的條件確定最大彎矩所在截面位置Ea1 + Ea 2 + Es1 - 一 E 2+ (13.9 + 0.75y)(y +1.85) + 5(y +1.85)2 -18.75y2 - (5y +18.5)y = 0 y = 2.22m彎矩為u 廠 h 2 p + p1.85 + 2.22 2p + p 、廠 1.85 + 2.22M = E x ( x4一Ob +1.85 + 2.22) + E x (x涕一Od) + E xa13 p + pa 23 p + ps13+1.85 + 2.22)37.8 +12.5152 x 1

9、2.515 + (15.29 +1.5 x 2.22)12.515 + (15.29 +1.5 x 2.22) +-E x 竺 + E :Wx 2+1.85 + 2.22)37.8 +12.5152 x 12.515 + (15.29 +1.5 x 2.22)12.515 + (15.29 +1.5 x 2.22) +1 85 + 222+ (13.9 + 0.75 x 2.22) x (2.22 +1.85) x (3x2.22 +1.852.225(2.22 +1.85)2 x318.75 x 2.222 x 3 +2.22 2 x 18.5 + (18.5 +10 x 2.22)、 (5

10、 x 2.22 +18.5) x 2.22 x (x)318.5 + (18.5 +10 x 2.22)=154.4KN - m=71.8MPa q =215MPaM _ 154.4KN =71.8MPa q =215MPa滿足要求。工況二:設置內(nèi)支撐，開挖至標高+1400m處，坑內(nèi)水位保持在標高+143。65m處(見圖2)。a。確定鋼板樁埋深計算原則:所有外力均對O點取矩，根據(jù)彎矩平衡確定埋深土壓力計算：主動土壓力：p a = qK 1 = 39 x 0.2 = 7.8 KPap b = (q + y 1 h)K 1 = (39 + 20.5 x 1.15) x 0.2 = 12.515KP

11、ap = (q +Y h +Yh )K = (39 + 20.5x 1.15 + 7.5x5.65)x0.2 = 20.99KPa a D11 11 2 a1p = (q + y h +yh )K 2c= (39 + 20.5x 1.15 + 7.5x5.65)x0.742 2x22x0.861 aD 21 11 2a 2a 2=40KPa TOC o 1-5 h z p = q +y h +yh +y(h + 1.2)K - 2c、k = 39 + 20.5 x 1.15 + 7.5 x 5.65 + 7.26 x (h +1.2) x 0.742 aF1 11 22 3a 2， a 23-

12、2 x 22 x 0.861 = 46.5 + 5.39h3 KPaE = i(p + p ) x h = 1 x (7.8 +12.515) x 1.15 = 11.681125奶 a112 aAaB12E = !(p + p ) x h =1 x (12.515 + 20.99) x 5.65 = 94.65KN a122 aBaD122E = !(p + p )x(h +1.2) = 1 x(40 + 46.5 + 5.39h )x(h +1.2) = (43.3 + 2.7h )(h +1.2)KN a 22aD 2aF 32333 3被動土壓力：p e = 2c質(zhì)=2 x 22 x

13、J1.347 = 51.1KPa p =y h K + 2c、：K = 7.26xh x 1.347 + 2x22x 1.347 = 9.78h + 51.1KPapF 2 3 p p33E = i(p + p )xh =1 x(51.1 + 9.78h + 51.1)xh = (4.89h + 51.1)h KNp 2 pE pF 323333水壓力計算：p =y (h +1.2 + h ) = 68.5 +10hsF w 233E 1 = 2p F X (h3 + h2 +1.2) = 5(h3 + 6.85)2p C =y x3 = 30E = 1(p + p ) x (h + 3.85

14、) = (49.25 + 5h )(h + 3.85) TOC o 1-5 h z s22 sC sF 333對O點取矩:- EX (k X pa paB + 0.15) + E X (么 X PaB* -DI 一 0.15) +a113 p + pm 3 p + pp + 2 p pep + 6.7)PpE + ppF廣 h +p + 2 p pep + 6.7)PpE + ppFE x ( x -f + 5.5) + E x (2- 0.15) - E x ( xa 23 p + ps13p-E X (h3 + 3.85 X psc+ 2PsF + 2.85) = 0 s23 p + p1

15、.15 2X7.8 +12.5155.65 12.515 + 2x 20.99 八-11.68 x (x+ 0.15) + 94.65 x (x0.15) +37.8+12.515312.515 + 20.99h +1.2 40 + 2x (46.5 + 5.39h )2(6.85 + h )(43.3 + 2.7h3 )(h3 +1.2)x( x+ 5.5) + 5(h3 + 6.85)2 x (-0.15).3h51.1 + 2 x (9.78h + 51.1)-(4.89h + 51.1)h x (t x3 + 6.7)-.3.;+ 2.85) = 030 + (68.5 + 10h3)

16、(49.25 + 5h )(h + 3.85)x A5x;+ 2.85) = 030 + (68.5 + 10h3)得 h = 4.7 m3鋼板樁入土深度應大于4。7m.b。計算支撐反力根據(jù)水平力平衡，E根據(jù)水平力平衡，Eq” + Ea12+ Ea 2+ E s1 一 一 E 2 一 = 0+ 94.65 + (43.3 + 2.7 x 4.7)(4.7 +1.2) + 5(4.7 + 6.85)2 - (4.89 x 4.7 + 51.1) x 4.7 -(49.25 + 5 x 4.7)(4.7 + 3.85) - R = 0得 R = 133.5 珈即支撐反力為133。5KN鋼板樁強度檢

17、算：由剪力等于零的條件確定最大彎矩所在截面位置(見圖3)p = (q + y h +y(3 + j )K = (39 + 20.5x 1.15 + 7.5x(3 + j )x0.2 = (17.015 +1.5j )KPa aH1 111 a111p h =y x (3 + j1) = 30 +10j1PsH+146.5m Ry1 Ea11PaAh1BPsH+146.5m Ry1 Ea11PaAh1BPaB常水位 +146.65mOi111111土層1CEay13+y1 Es11HPaH1 PsHq筑島頂+147.80mA坑內(nèi)水位+143.65m PsC -Es2 TOC o 1-5 h z

18、11E =-(p + p ) x (3 + y ) = x (12.515 +17.015 +1.5 y ) x (3 + y ) ay12 aB aH1211(14.765 + 0.75 y1)(3 + yKN設 H 點剪力為 0，E 11 + E 1 + E1 - E 2 - R = 0，+ (14.765 + 0.75y )(3 + y ) + 5(y + 3)2 - (30 + 5y )y -133.5 = 0 y = 1.77m111111彎矩為M = R x (2.85 +1.77) - Ex (、+ 3 +1.77) - Ex (1.77 + 3 x 七aB + P* ) -10

19、 x (1.77 + 3)3y1a113a1 y3 p + p 630 + 30 +10 x 1.771.77 2 x 30 + 30 +10 x 1.77+x 1.77 x x= 262.4KN - m330 + 30 +10 x 1.77-M 262.4KN , m鋼板樁應力。=122MPa v b =215MPaW2150cm 3滿足要求。工況三：混凝土封底、抽水后（見圖4）將封底砼看作一道支撐，則按1/2分擔法計算2道支撐結(jié)構(gòu)內(nèi)力。a.支撐反力及埋深計算H點為CG中點.土壓力計算：主動土壓力：p A = qK 1 = 39 x 0.2 = 7.8KPap B = 12.515KPap

20、h = (39 + 20.5 x 1.15 + 7.5 x 3.2) x 0.2 = 17.315KPap D1 = (39 + 20.5 x 1.15 + 7.5 x 5.65) x 0.2 = 20.99KPap d2 = (39 + 20.5 x 1.15 + 7.5 x 5.65) x 0.742 - 2 x 22 x 面壹=40KPap g = (39 + 20.5 x 1.15 + 7.5 x 5.65 + 7.26 x 0.6) x 0.742 - 2 x 22 x 際克=43.24KPap f = 39 + 20.5 x 1.15 + 7.5 x 5.65 + 7.26 x (

21、0.6 + h) x 0.742- 2 x 22 x J0742 = 43.24 + 5.39hKPa 被動土壓力：p e = 2 x 22 x J1.347 = 51.1KPap f = 7.26 x h x 1.347 + 2 x 22 x J1.347 = 9.78h + 51.1KPa水壓力:p h =y x3.2 = 32KPa p e =y x 6.85 = 68.5 KPa p g =y x 6.25 = 62.5KPa p f =y (6.85 + h) = 10h + 68.5KPa鋼板樁AH段的土壓力、水壓力由C點支撐承擔.2(p A + p B) x 1.15 + 2(p

22、 B + p H)x 3.2 + 2 p H x 3.2 = Rc得R = 1 x (7.8 +12.515) x 1.15 +1 x (12.515 +17.315) x 3.2 +1 x 32 x 3.2 = 110.6 KNC 222鋼板樁GF段上的主動土壓力、水壓力由EF段被動土壓力、水壓力和G點的支撐 各承擔一半。(p + p ) x (0.6 + h) + 上(p + p ) x (0.6 + h)=2 aG aF2 sG sF22(p+ p ) x h + 2(p + p ) x h = 2R得 h = 0.50m，Rgi = 61.6KN鋼板樁HG段的土壓力、水壓力由G點支撐承

23、擔。(p + p ) x 2.45 + L (p + p ) x 0.6 + L (p + p ) x 3.05 = R2 aH aD12 aD 2aG2 sH sGG 2R =1 x (17.315 + 20.99) x 2.45 +1 x (40 + 43.24) x 0.6 +1 x (32 + 62.5) x 3.05G2 222=216 KNRg = RG1 + Rg2 = 277.6KNC、G點的支撐反力分別為110。6KN、277。6KN,鋼板樁埋深應大于0。50m。b.鋼板樁強度檢算由剪力為零處確定彎矩最大值所在截面位置,a部分計算可得H面為剪力為零截 面M = 1(p + p ) X 1.15 X (115 X 2，aA + PaB + 3.2) +H2 aA aB3 p + p(p+p ) X 3.2 X ( X2 P aB* P aH ) + (p) X 3.2 X3.2 RR3 cx 3.05=2 X (7.8 +3.2 RR3 cx 3.05=2 X (7.8 +12.515) X 1.15 x (峙 x2 x 7.8 +12.5157.8 +12.515+3.2)+3.2 2 x 12.515 +17.31513.2x (12.515 +