实用标准文案精彩文档《基础工程》课程设计任务书——土木工程专业(道桥方向)一、设计题目某公路桥多排桩基础设计二、设计资料1.地质及水文河床土质:从地面至标高32.5m为软塑粘土,以下为密实粗砂,深度达30m。水文:地面(河床)标高为40.5m,一般冲刷线标高为38.5m,最大冲刷线标高为35.2m,常水位标高42.5m。2.土质指标软塑粘土:地基系数m=843/10mkN,桩周土的极限摩阻力kPa40,土的内摩擦角o20,土的容重3/12mkN(已扣除浮力)。密实粗砂:地基系数m=2543/10mkN,桩周土的极限摩阻力kPa120,土的内摩擦角o38,土的容重3/12mkN(已扣除浮力)。3.荷载上部为等跨25m的预应力梁桥,砼桥墩,承台顶面上纵桥向荷载为:恒载及一孔活载时:kNN4.5659kNH8.298(制动力及风力)mkNM7.3847(竖直力偏心、制动力、风力等引起的弯距)恒载及二孔活载时:kNN2.6498三、设计要求承台及桩的材料均为C20砼,承台尺寸:mmm0.25.40.7,拟定采用四根桩,设计直径1.0m,平面布置如下图。实用标准文案精彩文档要求:1、单桩容许承载力的确定;2、桩顶及最大冲刷线处荷载Pi、Qi、Mi及P0、Q0、M0的计算;3、最大弯距Mmax及最大弯距位置Zmax的计算;4、桩身截面配筋的计算;5、桩顶位移验算;6、桩基整体验算。四、时间安排时间计划表时间上午下午周一集中教室,布置设计内容单桩承载力计算周二桩顶荷载计算周三桩身内力计算周四配筋制图周五制图计算机出图五、设计成果1、设计说明书一份(A4纸)。2、设计图A3图纸一张(计算机出图)。图纸要求:(1)平面图、立面图、承台及桩身配筋图。(2)结构尺寸单位:除钢筋为mm外,其余均为cm。(3)有关工程数量表(包括钢筋kg、砼m3、钻孔m)。(4)有关说明。六、参考资料1、《基础工程》教材(人民交通出版社)2、《公路桥涵设计通用规范》3、《公路桥涵地基与基础设计规范》4、《公路钢筋混凝土与预应力桥涵设计规范》5、《结构设计原理》教材实用标准文案精彩文档详细计算书修改后荷载:上部为等跨的25m的预应力桥梁,砼桥墩,承台底面上纵桥向荷载为:恒载及一孔活载时:kNkNkNN4.7234)0.25.40.7(254.5659kNH8.298(制动力及风力)mkNmkNmkNM.3.4445.)0.28.298(7.3847(竖直力偏心、制动力、风力等引起的弯距)恒载及二孔活载时:kNkNkNN2.807325)0.25.40.7(2.6498桩基础采用冲抓锥钻孔灌注桩基础,为摩擦桩。1、计算桩长:(1)每根桩柱承受的荷载为:两跨恒载反力为:kNkNGN35.2018/44.80734/)(台局部冲刷线以上桩(直径为1.0米)自重每延米:)(781.114/10250.12kNq局部冲刷线以下桩(直径为1.0米)自重每延米:)(356.24/1012250.12kNq用《公路桥涵地基与基础设计规范》(JTGD63-2007)确定单桩轴向受压承载力容许值经验公式初步反算桩长,设该桩埋入局部冲刷线以下深度为h,一般冲刷线以下深度为3h,则:)3(21322001hrkfmAlqRNaPiniikah其中:mdu14.3kPaqk401kPaqk1202ml7.21mhl7.22mdAP785.04/)(280.00m70.00kPafa55000.62k32/12mkNhh3.3333.312655070.080.0785.0)7.2(1207.24014.321hhRa=-87.84+220.05hhNh356.2781.11)0.22.355.40(4/4.8073=h356.218.2057令:haNR解得:mh85.9现取mh11则桩底高程为:24.2m,桩总长为:14.3m由上式计算知:当mh11时2332.71kPa11220.05-87.84220.05h+-87.84aR实用标准文案精彩文档096.2208311356.218.2057356.218.2057=ahRkPahN(上图尺寸单位:cm)则知桩的轴向受压承载力满足要求。2、桩的内力计算(1)确定桩的计算宽度1b(mdmd0.10.1))1(.1dbf其中:9.0fkmd0.11122.6.01hLbbk因为:2n则6.02bmdL5.1)5.2(2mdhmhh6)1(31111所以:767.065.16.06.016.0kmb381.10.29.0767.01(2)计算桩的变形系数:实用标准文案精彩文档51EImb431/108mkNm432/1025mkNm440491.064mdI27/1055.28.08.0mkNEEcmh7.21mh3.82mhm11因为桩穿过双层地基,且2.0245.01mhh,则:2883.0)117.21(25.11)1(25.11221mhh43321/0989.201025)2883.01(1082883.0)1(mkNmmm488.00491.01055.28.0381.1100989.2057351EImb桩在局部冲刷线以下深度mh11,则其计算长度为:mmhh5.2368.511488.0故按弹性桩计算。3、桩顶刚度系数pp,HH,MH,MM值计算:00011ACAEhlpp其中:ml3.302122785.04mdA330/0879.22111100989.20mkNmhC0002211582.3311383.8207.2hhh0A22222091.45.24416.14)4582.33.tan2(mSmhd故取2091.4mAEIpp679.091.4100879.22111055.28.0785.011213.3137EIEIEIQHH03090.026585.0488.033EIEIEIMMH10763.045196.0488.022EIEIEIMMM52076.006713.1488.04、计算承台底面原点0处的位移0,0,0c(单孔+恒载+制动力等)EIEInNPP623.2663679.044.7234c02212120)()(MHniiPPMMHHMHniiPPMMnnnMnHn实用标准文案精彩文档EIEIEInniiPPMM32679.6)25.2(4679.052076.0412EIEInMH43052.010763.04EIEInHH12360.003090.04EIEIEIEIEIEI058.637643052.032679.612360.03.444543052.08.29832679.620EIEIEIEIEIEInnnHnMnMHniiPPMMHHMHHH488.113643052.032679.612360.08.29843052.03.444512360.0)(221205、计算作用在每根桩顶上的作用力iP,iQ,iM;竖向力:)488.113625.1623.2663(679.0)(00EIEIEIcPiPPi=kNkN006.844194.2773水平力:kNEIEIEIEIQHMHHi700.74488.113610763.0058.637603090.000弯矩;mkNEIEIEIEIMMHMMi.418.94058.637610763.0488.113652076.000校核:kNHkNnQi8.2988.298700.744mkNMmkNnMPiiinii.3.4445.3.4445418.94-425.1)006.844194.2773(21)(kNNkNPnii4.7234400.7234)006.844194.2773(2416、计算局部冲刷线处桩身弯矩0M,水平力0Q,及轴向力0.P;mkNlQMMii.092.1523.3700.74418.9400kNQQi700.740kNqlPPi071.2812781.113.3194.2773'00.7、局部冲刷线以下处桩截面的弯矩zM及桩身最大弯矩maxM计算:(1)局部冲刷线以下处桩截面的弯矩zM计算MMMMMMzBABABMAQM092.152074.153092.152488.0700.7400无量纲系数MMBA,由附表3、附表7分别查得,zM计算列表如下:ZZZMAMBMAQ0MBM0zM0.00.000.000001.000000.00152.09152.090.20.410.196960.9980630.15151.80181.950.40.820.377390.9861757.77149.99207.760.61.230.529380.9586181.03145.80226.830.81.640.645610.9132498.83138.90237.721.02.050.723050.85089110.68129.41240.091.22.460.761830.77415116.62117.74234.361.42.870.764980.68694117.10104.48221.58实用标准文案精彩文档1.63.280.737340.59373112.8790.30203.171.83.690.684880.49889104.8475.88180.712.04.100.614130.4065894.0161.84155.842.24.510.531600.3202581.3748.71130.082.44.920.443340.2426267.8636.90104.762.65.330.354580.1754654.2826.6980.962.85.740.269960.1197941.3218.2259.543.06.150.193050.0759529.5511.5541.103.57.170.050810.013547.782.069.844.08.200.000050.000090.010.010.02(2)桩身最大弯矩maxM及其位置计算:由0zQ得:9936.0700.74092.152488.000QMCQ及mmh0.4368.5取mh0.4查附表13,得:mZ959.0max故mZ97.1488.0959.0max由mZ959.0max及mh0.4查附表13得:610.1MK则:).(868.244092.152610.10maxmkNMKMM8、局部冲刷线以下深度处横向土抗力zxp计算:BZAZBZAZBZbMAZbQpzx227.26397.26381.1092.152488.0381.1700.74488.0210210无量纲系数BA,由附表1、附表5分别查得,zxp计算列表如下:ZZZABXAZbQ10xBbM