加筋挡土墙设计说明

1、加筋土挡土墙设计说明评语:成绩:签名:目录第1章设计资料.1.第2章筋带受力计算1.第3章内部稳定性验算 3.第4章外部稳定验算 .5.加筋挡土墙设计说明1. 结构尺寸设计设计各项计算资料汇列如下：(1) 挡土墙不受浸水影响，墙高H=10m，顶部填土 0.6m，基础埋深2m ；路基宽24.5m，路面宽18m ；(3)荷载标准：公路一级；面板规格：1.5m 0.8m，十字形混凝土板，板厚 20cm，混凝土强度等级 C20。(5)筋带采用聚丙烯土工带，带宽为18mm，厚2.0mm ,容许拉应力二=50MPa，摩擦系数 f=0.4；筋带节点间距：Sx =0.42m,Sy =0.4m ；填料：砂性土，

2、重度 20kN/m3，内摩擦角32，粘聚力c=0kPa ；(8) 地基：砂性土，重度 20kN/m3，内摩擦角32，粘聚力c=0kPa，地基承载力标准值fa =600kPa ；(9) 墙体采用矩形断面，加筋体宽为10.0m ；(10) 墙顶填料与加筋土填料相同，横坡为6%,摩阻系数为亠=0.36 。2. 筋带受力计算(1)计算加筋体上填土重力换算为等代均布土层厚度0 :已知H = 10m, a = 0.5m,m二1.5m, H0.6m，等代均布土层厚度计算如下：1H1h1( a)(5-0.5) = 3m H = 0.6m，故取 h = H = 0.6m。m21.5(2) 计算车辆荷载换算成等代

3、均布土层ho : 墙高 H _10m 时，q=10kN/m3。则 h0 二 q/孑=10/20 = 0.5m，ho=1.1m。(3) 筋带受拉计算：筋带受拉拉力包括三个部分：车辆荷载，墙顶路堤填土和墙后填料引起的筋带拉力。中：静止土压力系数：k=1 -sin =1-sin32 =0.470 ；主动土压力系数：ka =tan2(45 _32 /2) =0.307 ；Hh当 h _ 6m 时，k = ko (1) ka ;当 h 6m 时，k = ka ； bc=0.9m。66加筋体我度孟处，附加竖直压应力勺的扩散宣度-(ill).可按下式计算:Lci = G十久邑产+ H Lct = c + +

4、 Zj + H上 2AC)為=i h。二丁 =心(！ g 2 h2 ；爲)Sx SyLci筋带编号hi(m)kiLci(m)Lc(m)(Tai(kpa)Y 1hi(kpa)Y 2h2(kpa)Sx(m)Sy(m)Ti(KN)10.20.4725.824.59.504220.420.42.8020.60.4526.2524.59.3312220.420.43.29310.4426.4524.59.2620220.420.43.7841.40.4326.6524.59.1928220.420.44.2451.80.4126.8524.59.1236220.420.44.6762.20.4027.0

5、524.59.0644220.420.45.0672.60.3927.2524.58.9952220.420.45.42830.3827.4524.58.9360220.420.45.7593.40.3627.6524.58.8668220.420.46.05103.80.3527.8524.58.8076220.420.46.31114.20.3428.0524.58.7384220.420.46.54124.60.3328.2524.58.6792220.420.46.731350.3128.4524.58.61100220.420.46.89145.40.3028.6524.58.551

6、08220.420.47.02155.80.2928.8524.58.49116220.420.47.12166.20.3129.0524.58.43124220.420.47.97176.60.3129.2524.58.38132220.420.48.371870.3129.4524.58.32140220.420.48.78197.40.3129.6524.58.26148220.420.49.19207.80.3129.8524.58.21156220.420.49.60218.20.3130.0524.58.15164220.420.410.01228.60.3130.2524.58.

7、10172220.420.410.422390.3130.4524.58.05180220.420.410.83249.40.3130.6524.57.99188220.420.411.24259.80.3130.8524.57.94196220.420.411.65拉筋容许应力各层筋带长3. 内部稳定性验算 已知筋带断裂强度标准值fk =150MPa，抗拉容许应力卜丨- 50MPa ,提高系数k =1，筋带厚度为2mm利用容许应力法计算结果见下表：筋带编号Ti(KN)需要筋带面积mm2选取根数安全系数12.8056.0031.9323.2965.8031.6433.7875.6052.384

8、4.2484.8052.1254.6793.4051.9365.06101.2051.7875.42108.4051.6685.75115.0051.5796.05121.0051.49106.31126.2051.43116.54130.8051.38126.73134.6051.34136.89137.8051.31147.02140.4051.28157.12142.4051.26167.97159.4071.58178.37167.4071.51188.78175.6071.44199.19183.8071.37209.60192.0071.312110.01200.2081.4422

9、10.42208.4081.382310.83216.60101.662411.24224.80101.602511.65233.00101.55(2)筋带长度计算计算各层筋带在活动区、锚固区的长度及总长。设计中加筋体为矩形断面,度均为8m简化破裂面的垂直部分距面板背部的水平距离为：bH =0.3 H =3m32 简化破裂面下段高度：H2 =bH tan(45)=3 1.804 = 5.412m简化破裂面上段高度：H1 =:H 一日2 =10一5.412 =4.588m(3)抗拔稳定性填料与筋带间似摩阻系数取0.4，抗拔力调节系数查表得戎=1.4。筋带长度由公式Li二Lfi - Lai计算而得

10、。活动区的筋带长度可按下图所示公式计算：Lfi = 0.3W(0 司 凤)Lfi = H -知 tan 453 + #(Hl zf 10374.855B. 墙面的被动土压力Ep计算GN + %乙+昭-_232_路基底面C点处水平压力Pc =20 2 tan2(45)=130.184kPa所以，Ep =0.5 130.184 2 =130.184kPaC. 各力对基底重心 O点的力矩Mg =G, h G2 l2 G3 l3 = -5.4 (4 -1.1) 145.2 (4.7 -4) 1600 0 =85.98kN mMa =374.855 (10 -6.366) = 1362.223kN m

11、M p -130.184 0.67 = 87.223kN m所以，M =Ma M p M g =1189.02kN mD. 基底合力偏心距及地基应力计算_ M 1189.02 ccc LE0.68m1.33m1750.666e1750.60.636219.30kPa ： P =350kPa8886e1750.60.636218.35kPaL L88满足要求。(2)基底滑移稳定验算RnaxminN - _ N -L _ N】.1C 4加(号+&1朗时-加总ptanoj M 4 ( i, 1(； *%兮)畑口為加 *弊坨E厂 Mana0式中：G一 用于皐底以上的重力(讪人 浸水挡七墙的浸水部分应计

12、入浮力；耳墙踰主动土压力的轻向分fit (kN)；駄墙時主动七压力的水平分量(kN)；孙墙曲被动土压力的水平分虽(kN),当为屁水挣土圾时* E严0;E；境前被动土压力水平分量的G3倍(kN);N柞用于基底上合力的竖向分力(kN).浸水挡丄墙应计浸水部分的浮力; 偽莘底倾斜角基底为水平时*规范规定，当荷载组合n时，要求的基底滑移稳定系数K=1.3，取基底摩擦系数为 - 0.36 , Kc =上二=嚎1評二2.397 1.3，基底滑移稳定性满足要求。(3)倾覆稳定性验算式中；乙；墙身重力.基础重力、基础上填土的堕力及作用于塔m的其他枸载的竖向 力含力觅心列缢趾的距离(rn)；兀墙后主动土歩力的竖向分就到墻甜的断离(rn)；Zv墙后主动土压力的忒平分塑到墟趾的距离(m) *心墻前被动卜压力的水平分倉到墙趾的距离 5)。A. 各点对墙趾点的力矩计算Mg =5.4 1.1145.2 4.7 1600 4 =7088.38kN mMa =374.8