钢板桩围堰计算单

1、桂林南洲大桥P2主墩钢板桩围堰计算单计 算: 复 核: 项目负责: 总工程师:中铁大桥局集团二公司设计部二oo五年一月一、概况桂林市南洲大桥位于桂林市叠彩区大沙乡境内，全长320mo跨径组合为(50+87+144+39) m,其中87m和144m为曲塔双索面斜拉桥，斜拉桥东西两侧各 接50m辅道孔和39m过渡孔。斜拉桥釆用塔梁固接扇形双索面结构形式，主跨采 用钢栓叠合梁，边跨釆用预应力栓梁。主墩下设两个相对独立的直径D二21m的圆 形承台，每个厚度为5m。承台布置24根<1> 1. 5m钻孔桩和6根备用桩。承台底标 高+141. 0m,顶标高+146. Om,常水位+146. 65

2、m,筑岛顶+147. 8m。从技术、经济两方面考虑，P2主墩的承台施工采用SP-U400型钢板桩，其 规格为：宽度 b二400mm,高度 h二 1600mm,腹板厚 16. 0mm：重量76. lkg/m,每米惯性距34400cm:,每米截面模量2150cm3二、设计计算1、封底厚度(根据简明施工计算手册P339计算)封底栓采用C20,设封底厚度为h静水压力对封底栓形成的荷载p = yw(146.65 -141.0 + h) - 24h = 56.5 -？按简支双向板进行计算人=6.6加,/2= 6.647m, /,/, =0.99查表得d = 0.0429,M = dpi；,Mmax = M

3、 = 0.0429 x(56.5-14/?)x6.62 =105.6-26.16/K = 2.65, D = 0.35m, b = m, fcl =1AN / mm2取封底卑度为1. 2mo基坑除土完毕后须检查坑底各处标高均不大于+139. 8m,各处封底栓均应保 证1.2m厚。2、各工况钢板桩埋深及强度计算(根据深基坑工程设讣施工手册讣算) 各土层地质情况：土层1：天然容重儿=205KN/?3浮容重“=75KN/加6粘聚力q =0,内 摩擦角 © =42°, KaX = tan2(45-) = 0.2, Kp = tan2(45 +) = 5土层2：天然容重/ =183K

4、N/几 浮容重冗=726KN/w3粘聚力c2 = 22KPa ,0.742 , Kq = tan "45 +号)=1.347内摩擦角 <p2 = 8.5° , Ka2 = tan2 (45-) =取1米宽钢板桩进行计算，设围堰顶有施工荷载q = 39KPa。工况一：钢板桩插打完，开挖圉堰内土体至标高+144.8时（见图1）a. 确定钢板桩埋深计算原则：所有外力均对D点取矩，被动土压力产生的力矩须大于主动土压 力产生的力矩。土压力计算：主动土压力：paA = qKaX =39x 0.2 = l.SKPa pali =(q + 汕)K“| = (39 + 20.5 x 1

5、.15) x 0.2 = 12.515 KPa paD = (q + 儿力+ yJg)Kai = 39 + 20.5 x 1.15 + 7.5x(/73+1.85) x 0.2 = (15.29 + .5h3)KPaE;1 = (p<lA + paB) x /i, = x (7.8 +12.515) x 1.15 = 11.68A7V 2 2Ea2 =-(p(lB + paD )x/?2 =丄 x (12.515 +15.29 +1.5A3) x (1.85 + 禺)=(13.9 + 0.75屁)他 +1.85) AN 2 2被动土压力：PpD = yJjK 口 = 7.5 xh3 x5

6、 = 37.5h3KPa1 1,Ep = p卩。x/?3 = x 37.5/:3 x/?3 = 1 &75竝 KN2 2水压力计算：pxD =人(185 + 力3)= 18.5 +10方31 乍 = p$D x(3 +1.85) = 5(他 +185)2psC = yw x 1.85 = 18.5E$2 = g (代C + PsD)X 3 =?3 + 1.85)/?对D点取矩:E“ x ( x J"”' + 几 +/?2) + En, x (乞 x 2几 + 几")+ EU x-E X + *33 paB + paD336x(如x込皿)=02 PsC + P

7、sD11.68xx 二% j_+ 匕"3 + 1.85+ /?,) +(13.9 + 0.75/?3) x (/?3 + 1.85)x37.8 +12.5151.85 + /1,2x12.515 + (15.29 + 1.5仏)、 心 +1.85仏312515 + (1529+15禺)33心/?.2xl8.5 + (l &5 + 10人)、八(5人 +18.5)仏 x(x ) = 0318.5 + (1 &5 + 10 人)/?3 = 4. m钢板桩入土深度应大于4. Imob. 钢板桩强度检算：山剪力等于零的条件确定最大弯矩所在截面位置Em + 已池 + Eh Ep

8、 Ex2 = 0 11.68+ (13.9 + 0.75y)(y +1.85)+ 5(y + 1.85)2 -18.75/ -(5y+ 185)y =0y = 2.22m弯矩为M=Enix(-x 2/土 滋 + 1.85 + 2.22) + x(空二x込二啦)+ 础 x 川、-2.22 3 PaA + 几B3 pQli + paD3厂 2.22 厂 2.22 2p« + 卩山、丄 15 2x7.8 + 12.515 、一 E xf Ej x (x ) = 11.68 x (x+ 1.85 + 2.22)3 一 3 psC + psD37.8 +12.515"小err1.85

9、 + 2.22 2x12.515 + (15.29 + 1.5x2.22),+ (13.9 + 0.75 x 2.22) x (2.22 + 1.85) x (x) +312.515 + (15.29 + 1.5x2.22),2.22 + 1.857 2.225(2.22 +1.85)2 x1 &75 x 2.221 x +33gE ,2.22 2x18.5 + (18.5 + 10x2.22)(5 x 2.22 +18.5) x 2.22 x (x)318.5 + (1 &5 + 10x2.22)=154.4KN mMb =：W1 54 4KN m满足要求。工况二：设置内支撑

10、，开挖至标高+140. Om处，坑内水位保持在标高+143. 65m处(见图2)。a.确定钢板桩埋深计算原则：所有外力均对0点取矩，根据弯矩平衡确定埋深土压力计算：主动土压力：p© = qK" = 39 x 0.2 = l.SKPapaii =(q + 人力)K“ = (39 + 20.5 x 1.15) x 0.2 = 12.515 KPapaD = (? + /|/?j + yhKaX = (39 + 20.5 x 1.15 + 7.5 x 5.65) x 0.2 = 20.99 KPapaD1 = (q + /hl +-2cJk心=(39 + 20.5x 1.15 +

11、 7.5x5.65)x0.742-2x22x0.861=40KPapaF =q + M + yh2 + y2(他 +1.2)Ka2 一= 39 + 20.5xl.l5 + 7.5x5.65 + 7.26x(禺 +1.2)x0.742 -2x22x0.861 = 46.5 + 5.39h3KPaPsCEs2PsF EallPaAhl+146. 5m R B坑内水位+143. 65m CEal2PaBh2筑岛顶+147.80m常水位 +146.65m土层1PaD2 . PaDlI+141. Omh3Ea2Esl+139. 8m土层2PaFPsF图2工况二Eali =丄(几a+pQx/I =-x (

12、7.8 + 12.515)x1.15 = 11.681125/OV2 2E=丄(PaB + PeJxh?=丄 x (12.515 +20.99) x 5.65 = 94.65KN2 2Eal =-(paD1 + 卩丽)x (力3 +1.2)=丄 x (40 + 46.5 + 5.39屁)x (禺 +1.2) = (43.3 + 2.7 禺)他 +12) KN 2 2被动土压力：p pe = 2cJ K p = 2x22x J1.347 =5.KPaPpF = yJgKp + 2c 貞=7.26 x/i3x 1.347 + 2x22x J1.347 = 9.78/?3 +51 KPuEp = _

13、(PpE + P pF) x $ = x(51.1 + 9.78/?3 +51.1)x/?3 = (4.89 仏 + 51. l)/“ KN 2 2水压力计算：psF =(h2 +1.2 + h3) =68.5 + 10/z3Esi = PsF x (方3 + 鬼 +1.2) = 5(/?3 4- 6.85)2Pg = x 3 = 30Es2 = (Psc + PsF) x (% +3.85) = (49.25 + 5h3)(h3 +3.85)对0点取矩：為X(如X汕如+ 0.15) +岛川(如严厂2几0+3 PaA+ PaB3 PaB + pal)x+ 6.7)Sx(gHx沁上如+ 5.5)

14、 + Sx(型土血°5)-d x(xZ+2/V 3 paD2 + paF33 ppE + PpF瓦2班仝兰>< 心如+ 2.85)“3 PiC + “J.15 2x7.8 + 12.515 八心门一.,.65 12.515 + 2x20.99 n 1C4一1 l68x(x+ 0.15) + 94.65x(x一015) +37.8 + 12.515312.515 + 20.99(43.3+2.7 妇)(人+1.2)x(如上12 x 竺仝佟士空垫2+5.5)+5(尽+6.85) 2x(竺空1如-0.15)53340+(46.5 + 5.39/?；)3_(4.89仏 +51.1

15、)人 x(厶x .y "%/匕-、1+ 6.7)_351.1 + (9.78人+51.1)(49.25+5阳他+3.85)x(空邑沁竺如+ 2.85) = 0330+(68.5 + 10%)得仏=4.7m钢板桩入土深度应大于4. 7m。b. 计算支撑反力根据水平力平衡,Eali + Eal2 + Eal + Esl-Ep-Es2-R = 011.68 + 94.65 + (43.3 + 2.7x4.7)(4.7 + 1.2) + 5(4.7 + 6.85)2 -(4.89x4.7 + 51.1)x4.7-(49.25 + 5x 4.7)(4.7 + 3.85)-R = 0得 RT33

16、.5KN即支撑反力为133. 5KNc. 钢板桩强度检算：山剪力等于零的条件确定最大弯矩所在截面位置(见图3)paH = (q + 儿力+儿(3+ ”)«, = (39 + 20.5x 1,15 +75x(3 + yj) x02 = (17.015 + l5y】)KP"Psh =/bx(3 + y1) = 30 + 10ylEayi = g(几B + 几“)x(3 +yj = *x (12.515 +17.015 +1.5yjx (3 +力)=(14.765 +075”)(3+”)KN设 H 点剪力为 0, EflI1+EflVl+Evl-£n-/? = 0, 1

17、1.68 + (14.765 + 0.75yxX3 + y) + 5(y, +3)330 + 30 + 10x1.77钢板桩应力"沪驾霁! = 13=2/满足要求。工况三：混凝土封底、抽水后（见图4）将封底栓看作一道支撑，则按1/2分担法讣算2道支撑结构内力。a.支撑反力及埋深计算H点为CG中点。土压力计算：主动土压力： 一(30+ 5戸)比-133.5 = 0 儿=T!m弯矩为=/?x(2.85 + 1.77)-£：flII x( + 3 + 1.77)-Enlv x(L7?+3 x 2/?Z?n/)- x (1.77 + 3)33几+几6=262 A KN m30 +

18、30 + 10x1.77 ,严 1.772 x 30 + 30 + 10x1.77Pei = KaX = 39 x 0.2 = 78KPa几b =12.515 KP"palt =(39 + 20.5x1.15+ 7.5 x 3.2) x 0.2 = 17.315 KPapal) = (39 + 20.5 x 1 15+7.5x 5.65) x 0.2 = 20 9) KPa pal)1 = (39 + 20.5 xl.l5 + 7.5x 5.65) x 0.742-2x22x J0.742 = 40KPapaG = (39 + 20.5 xl.l5 + 7.5x 5.65 + 7.2

19、6 x 0.6) x 0.742-2x22x J0.742 = 43.24KP"paF =39+ 20.5 xl.15 + 7.5x5.65 + 7.26 x (0.6 + h)x 0.742-2x22x J0.742 = 43.24 + 5.39hKPa 被动土压力：PpE =2x22x71.347=51 .KPaPm = 7.26 x x 1.347 + 2 x 22 x J1.347 = 9.78/? + 51. IKPg水压力：Pm =/wx3.2 = 32KPapsE = yw x6.85 = 6S.5KPaPw = yw x 6.25 = 62.5KPaP$f =人(6.

20、85 + h) = 107/ + 68.5KP"钢板桩AH段的土压力、水压力山C点支撑承担。£(P朋 + 几出)X1 15 + *(几b + #“) x 3.2 + g psll x 3.2 = Rc得/?c =1x(7.8 + 12.515)x1.15 +-x (12.515 +17.315)x3.2 + -x32x3.2 = 110.6K7V2 2 2钢板桩GF段上的主动土压力、水压力由EF段被动土压力、水压力和G点的支撑 各承担一半。* (Pm + PaF) x (0.6 + /?) + £ (卩皿 + psF) X (0.6 + 力)=2* (% +PpF

21、)+ -(PsE +PsF ) X 加=2RGl得力= 0.50?，RGl = 61.6KN钢板桩HG段的土压力、水压力由G点支撑承担。£(几 + PaD)X 2.45 + |(/<1D2 + PaG)X °6 + g (几 + p iG) x 3.05 = Rg2Rg2=丄 X (17.315 + 20.99) x 2.45 + 丄 x (40 + 43.24) x0.6 + -x (32 + 62.5) x 3.052 2 2= 216KW心=岛 +% =277.6KNC、G点的支撑反力分别为110.6KN、277. 6KN,钢板桩埋深应大于0.50m。b.钢板桩强度检算由剪力为零处确定弯矩最大值所在截面位置，a部分计算可得H面为剪力为零截 面M H = (Pa, + Pan )x1 1 5 X (7- X - + 3.2) +23 paA + pali+ 几)x 3.2 XF) + d几)X 3.2 X 二 一 /?c x 3.0523 pai + paH 231 宀 cu152x7.8 + 12.515 小小=x (7.8 +12.515) x 1.15 x (x+ 3.2) +2 37.8 + 12.5151 "cucc z3.2 2x 12.515 +17.31