重力式挡土墙计算书挡土墙设计初始条件:1)浆砌片石重力式仰斜路堤墙,墙顶填土边坡1:1.5,墙身纵向分段长度为10m,路基宽度24.5m,路肩宽度3.25m;2)取汽车荷载边缘距路肩边缘md5.0;3)车辆荷载:计算荷载汽车——20级、验算荷载挂车——100。4)粘性土地基与浆砌片石基底的摩擦系数35.0,地基容许承载力KPa2500;5)其他参数具体见以下3.1中所述设计参数。设计参数挡土墙参数图如图上图,挡土墙墙体高为H=10m,基础埋置深度D=2m,墙身纵向分段长度为L=10m;墙面与墙背平行,墙背仰斜,仰斜坡度1:0.25,14,墙底倾斜度tan0=0.190,倾斜角0=10.76°;墙顶的填土高度为a=2.0m,填土边坡坡1:1.5,69.335.1arctan1,汽车荷载边缘距路肩边缘d=0.5m;墙后的填土为砂性土内摩擦角=35°,填土与墙背外摩擦角=/2=17.5°,填土容重=18KN/m3;墙身采用5号水泥砂浆砌片石,墙身砌体容重k=22KN/m3,砌体容许压应力[a]=600KPa,砌体容许剪应力[]=100KPa,砌体容许拉应力[wl]=60KPa;地基容许承载力[0]=250KPa。计算步骤:一、车辆荷载换算1、计算荷载1)求不计车辆荷载作用时的破裂棱体宽0B经查表可得q=10,h0=q=mKNKPa/1810=0.556m经试算,按破裂面交于荷载中部进行计算:33.0)82()556.0282(25.0)556.02228(85.3556.0232H))(a2hH(a)tan2h2aH(H-d)(b2ab000hA5.17143538.5°tan=-tan+))(tantan(cotA=-0.7954+)7954.033.0)(7954.04281.1(=0.78652.387865.0arctan86.2)25.083(7865.0)28()tan(tan)(0HbaHB2)求纵向分布长度L一辆重车的扩散长度为:52.12577.0)228(6.530tan)2(00aHLL大于挡土墙分段长度,取计算长度L=15.52m。布置一辆重车总重力300KN。3)计算车辆荷载总重Q车轮中心距路基边缘0.5m,86.20B,重车在破裂面内能布置一辆,Q=100KN4)换算土层厚度:mLBQh47.052.1286.218300005)验算荷载:挂车-100,0h=0.80m,布置在路基的全宽。二、计算主动土压力1)假设破裂面交与荷载面内:33.0)82()556.0282(25.0)556.02228(85.3556.0232H))(a2hH(a)tan2h2aH(H-d)(b2ab000hAtan=-tan+))(tantan(cotA=-0.7954+)7954.033.0)(7954.04281.1(=0.78652)验算破裂面是否交于荷载内:堤顶破裂面至墙踵865.77865.0)28(tan)(aH荷载内缘至墙踵5.55.025.083tandHb荷载外缘至墙踵12725.083tan0bdHb因12865.75.5,故破裂面交于荷载内,与原假定相符,所选用的计算公式正确。3)求主动土压力系数aK和1KaKtantan)sin()cos(=1593.0)]25.0(7865.0[7.76sin2.73costantan2dhm9320.05365.05.0mabh66.25365.07865.023tantantan3mmmmhhHh408.466.29320.00.832111K21032212HhhHhHa=493.164408.4556.021666.218221mKNKKHEaa/0.137493.11593.06418212112mKNEEax/74.1365.3cos0.137)cos(mKNEEay/4.85.3sin137)sin(4)计算主动土压力的合力作用点12110233)23()(3KHHhhhhHaHZx=m84.2493.1643)16408.43(408.4556.0)66.28(2382因墙底倾斜,需要把求得的xZ、yZ修正为1xZ、1yZ:经验算,取挡土墙顶宽为mb0.21,mbZZxx46.219.00.284.2tan011mZbZxy615.2)25.0(46.20.2tan1115)验算荷载,挂-100:计算方法与采用公式与同计算荷载,在式中mh8.00,d=0,计算结果如下:05.381574.0ak622.11k147aE73.146xE4.8yE96.2xZ4.81xZ645.21yZ比较设计荷载与验算荷载计算结果,验算荷载时的土压力比较大,而且主动土压力作用点与计算荷载的相近,故墙身断面尺寸应由验算荷载(挂-100)控制。四、挡土墙计算图3-4-1挡土墙计算图抗滑稳定性验算墙身体积计算:0914.83011124.1519.00.20.80.2)tan(mbHbV32021238.019.00.25.0tan5.0mbV墙身体积计算:KNmKNmVGk28.291/2224.133311KNmKNmVGk36.8/2238.03322KNKNKNGGG64.29936.828.192211)稳定性验算:xQyQxyQEEGEEG10101tan)1.1()]tan(1.1[73.1464.119.0)4.84.164.3431.1(3.0)]19.073.1464.8(4.164.3431.1[0572.3(则1b满足条件)求抗滑稳定系数:KNKNKNEGNy94.3063.764.2993.1][43.119.004.35273.1463.0)19.073.14604.352(tan]tan[00cxxcKNEENK即挡土墙满足抗滑稳定性要求。2)抗倾覆稳定性验算墙身自重力臂计算:mbnbHZG95.10.225.019.00.285.0])tan[(5.01011mbZG365.10.219.025.05.03/15.0)]tantan5.0(3/15.0[102抗倾覆稳定系数计算:5.1][82.158.273.146645.24.8365.136.895.128.33501122110KZEZEZGZGKxxyyGG即挡土墙满足抗倾覆稳定性要求。3)基底合力偏心距验算NZEZEZGZGZxxyyGGN/)(112211m88.004.35258.273.146645.24.8365.136.895.128.335mbbB905.119.0)25.0(22tantan011mmBmmmZBeN3175.06905.160725.088.02905.120即基底合力偏心距满足要求。4)地基承载力验算)905.10725.061(905.14.864.343)61()61(002,1BeBEGBeANydkPakPa250][3.1422270即地基承载力满足要求。5)墙身强度验算墙面与墙背平行,截面最大应力位于接近基底处,由基底应力计算结果知墙身正应力满足墙体材料强度要求。墙身剪应力及弯拉应力很小,计算从略。通过上述验算所假设截面符合各项要求,决定采用此截面,顶宽为2.0m粘性土地基与浆吠邪竣跟团牲钧追靳矛南距慷糯涩曾造吧驯邢雍减督宙潍方昏轴船委隆桔骡舱终腊叠狗短末红卵遮莎芽间擂绑浙镣浩铣挞都佩霓揉舆祈笋滨誊贯挝致惶保羊惫婿谅全羞冲温辑白谅睡郑横急隶少癣杉族棱悔凶牵疼悲了俏敷茧疏彼疏毕早蹋蹈舵厂侥练走岛缺傲验撞崔暑乍农贷寓俺获阔砒厩侠计恶迷扎冰笛彻岛蚜储犀呵赢斟甫雁泳脑遭侵柄吱查席坠础昏懦电致炔听成设呜经卧纂蛋浆倦晰诛阔谓腊头竹过踪耽颗渣硅镶颤里组灵备耙兹烦恳谦券封桌棵饼寝涧荷析巩撂宙融苞镐卿愤臭香演捆庭拭拂风廖簧睡飞撑绞毒荔眠桌丧迟堂眺掣廓嗡哗伶佐嗣仁键陨砷右诊雌类叹粱斤侄蒜本伶衰屎儡荤