某市环城快速路路堤加筋挡土墙支护设计

某市环城路路堤加筋挡土墙支护设计设计小组：张海富 杨岩 郭辉 陈侃 王守道一设计资料某市环城快速路K23+385.728K23+486.726路段的路堤，处于无石料地区，根据前期的勘察资料得知该区地基承载力相对较低。综合分析该工程的实际情况并进行初选方案比选后，拟采用加筋土挡土墙支挡结构类型。具体设计资料列于下：已知墙后土体为砂性土，=40，=18kN/m，土与拉筋之间的摩擦角 =20，地基承载力特征值 =100 kN/m。af1路线技术标准，山岭区一般二级公路，路基采用填方工程成型，路堤拟用加筋土挡土墙支挡。2地表有车辆荷载，计算荷载为汽车-20级，验算荷载为挂车-100，设计时简化为地表均布标准荷载pk=20kN/m。3挡土墙墙高H=12m。4地基土层的地基承载力相对较低，其允许承载力 =100 kN/m，混凝土底板与土的摩擦角 =30。6如无工程经验，拉筋可参考教材选取，相应参数可查找相应规范。7如设计中遇到实际问题，可在设计计算书中进行说明，并自行解决。af二.加筋挡土墙设计1.截面及结构设计 墙面板的形状为十字形，其高为0.6m，宽为0.8m，厚为0.15m。拉筋为矩形截面钢筋混凝土拉筋，其宽为0.1m，厚0.06m。拉筋布置在墙面板中心处，均匀分布在土中，垂直间距Sy=0.6m，水平间距Sx=o.8m。墙面板及拉筋材料均采用 C20混凝土，二级钢筋。2.荷载计算式中，b-荷载分布长度，即沉降缝宽度，一般采用10m -荷载分布宽度，采用四车道取13m -回填土重度（kN/m3)-分布范围内荷载总重，该处简化为均布荷载，取值为 l0Gm1.11885.1210260000blGh （1）土压力计算 按 H/2时，（2）活荷载引起侧向压力 按扩散角法计算荷载引起的水平土压力 （3）第i层拉筋对应的墙面板所受的侧压力 计算结果见表1-1hihiiiihhKp2.7012.435.001HKpiiiihLlhKp577.085.1296.1020002yxiixissppE)(21 4.拉筋长度计算 计算拉筋长度时，应计算拉筋有效摩擦阻力，计算每层拉筋计算处的垂直应力 ，它包含垂直土压力及荷载引起的垂直压力。即 式中（1）无效段长 按0.3H折线法计算：当 H/2时，pviiviivivviphppp221iiivhLlhp577.085.12131.118002Lfihim6.33.0HLfihi)12(6.0)(6.0iifihhHL （2）有效长度 (3)全长 垂直压力 计算见表 1-2，拉筋长度计算见表1-3，安全系数K取2.0按墙高12m，拉筋最小长度应大于0.8倍墙高，=0.8x12=9.6m，即按最小长度10m。拉筋最终长度：距顶6.0m深以下用12m，以上用10m。LaiviiviiaipTfapTL1.03.022xiiKET fiaiiLLLpviLi 4.分板稳定与全墙稳定计算（1）求单根拉筋抗拔系数式中，拉筋抗拔力 由于拉筋取整，其有效长度有所差异，设计选定拉筋长度为 ,则拉筋实际有效长度为式中，-第i层拉筋选定的长度 计算结果表见1-4，均大于2.0，分办抗拔稳定安全满足要求。0.2xifisiESKviaiaivifipLLfapS06.02LifiiaiLLpLi (2)全墙稳定 1）求全墙的抗拔稳定系数 满足全墙抗拔要求2）全墙的倾覆稳定性系数 满足全墙倾覆稳定性要求0.2358.388.37057.1245161161xifisESK0.2925.2416.1772734.51831611611611610iEibifiiEifiMhSMMKhi(m)P1i(KN)P2i(KN)侧压力Exi(KN)0.32.167.81 4.790.96.487.59 6.751.510.87.38 8.732.115.127.18 10.72.719.447.00 12.693.323.766.82 14.683.928.086.65 16.674.532.46.49 18.675.136.726.34 20.675.741.046.20 22.676.343.26.06 23.646.943.25.92 23.587.543.25.80 23.528.143.25.67 23.468.743.25.56 23.49.343.25.4523.359.943.25.3423.310.543.25.2423.2511.143.25.1423.211.743.25.0423.16表1-1hi(m)Li(KN)Pv2iPvi(KN)0.313.1919.5124.91 0.913.5718.9735.17 1.513.9518.4545.45 2.114.3317.9655.76 2.714.7117.566.10 3.315.117.0576.45 3.915.4816.6386.83 4.515.8616.2397.63 5.116.2415.85107.65 5.716.6215.49118.09 6.31715.14128.54 6.917.3814.81139.01 7.517.7614.49149.49 8.118.1414.19159.99 8.718.5213.9170.50 9.318.9113.61181.019.919.2913.34191.5410.519.6713.09202.0911.120.0512.84212.6411.720.4312.6223.2表1-2hi（m）无效长度Lfi(m)Ti(KN)垂直压力Pvi（KN/m）有效长度Lai（m）拉筋长度Li（m）0.33.69.5824.91 6.4110.010.93.613.535.19 6.4101.53.617.4645.40 6.4102.13.621.455.76 6.4102.73.625.3866.10 6.4103.33.629.3676.45 6.4103.93.633.3486.83 6.4104.53.637.3497.63 6.379.975.13.641.34137.75 6.4105.73.645.34107.65 6.4106.33.4247.28118.09 6.139.556.93.0647.16128.54 5.658.717.52.747.04139.01 5.247.948.12.3446.92149.49 4.897.238.71.9846.8150.99 4.576.559.31.6246.7170.54.35.929.91.2646.6181.014.055.3110.50.946.5191.543.834.7311.10.5446.4202.093.644.1811.70.1846.32212.643.463.64表1-3hi（m）有效长度Li（m）垂直压力Pvi（KN/m）抗拔力Sfi（KN）侧压力Exi(KN)抗拔系数Ksi0.38.424.91 12.55 4.792.620.98.435.17 17.73 6.752.6271.58.445.45 22.91 8.732.6242.18.455.76 28.10 10.72.6262.78.466.10 33.30 12.692.6243.38.476.45 38.53 14.682.6253.98.486.83 43.24 16.672.5944.58.497.63 49.21 18.672.6365.18.4107.60 54.26 20.672.6255.78.4118.09 59.52 22.672.6256.38.58128.54 50.75 23.642.1476.96.94139.01 57.88 23.582.4557.57.3149.49 65.48 23.522.7848.17.66159.99 73.53 23.463.1348.78.02170.50 82.04 23.43.5069.38.38181.5491.2623.353.9089.98.74191.54100.4423.34.31110.59.1202.09110.3423.254.74611.19.46212.64122.9923.25.30111.79.82223.2131.5123.165.678表1-4hi（m）抗拔力Sfi（KN）hbi=H-hi（m）Mfi=Sfi*hbiMeK00.312.55 11.7146.8351772.4162.9250.917.73 11.1196.8031.522.91 10.5240.5552.128.10 9.9278.192.733.30 9.3309.693.338.53 8.7335.2113.943.24 8.1350.2444.549.21 7.5369.0755.154.26 6.9375.3945.759.52 6.3373.0866.350.75 5.7289.2756.957.88 5.1295.1887.565.48 4.5294.668.173.53 3.9286.8068.782.04 3.3270.7329.391.262.7240.4029.9100.442.1210.92410.5 110.341.5165.5111.1 122.990.911.69111.7 131.510.339.453表1-5谢谢观看