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+385.728~K23+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/m³，土与拉筋之间的摩擦角=20°，地基承载力特征值=100kN/m²。 1．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/m²。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=100kN/m²，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。 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 （1）土压力计算按<=H/2时，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1-1 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，当>H/2时， （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。 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。 (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 hi(m)P1i(KN)P2i(KN)侧压力Exi(KN)0.32.167.814.790.96.487.596.751.510.87.388.732.115.127.1810.72.719.447.0012.693.323.766.8214.683.928.086.6516.674.532.46.4918.675.136.726.3420.675.741.046.2022.676.343.26.0623.646.943.25.9223.587.543.25.8023.528.143.25.6723.468.743.25.5623.49.343.25.4523.359.943.25.3423.310.543.25.2423.2511.143.25.1423.211.743.25.0423.16表1-1 hi(m)Li"(KN)Pv2iPvi(KN)0.313.1919.5124.910.913.5718.9735.171.513.9518.4545.452.114.3317.9655.762.714.7117.566.103.315.117.0576.453.915.4816.6386.834.515.8616.2397.635.116.2415.85107.655.716.6215.49118.096.31715.14128.546.917.3814.81139.017.517.7614.49149.498.118.1414.19159.998.718.5213.9170.509.318.9113.61181.019.919.2913.34191.5410.519.6713.09202.0911.120.0512.84212.6411.720.4312.6223.2表1-2 hi（m）无效长度Lfi(m)Ti(KN)垂直压力Pvi（KN/m²）有效长度Lai（m）拉筋长度Li（m）0.33.69.5824.916.4110.010.93.613.535.196.4101.53.617.4645.406.4102.13.621.455.766.4102.73.625.3866.106.4103.33.629.3676.456.4103.93.633.3486.836.4104.53.637.3497.636.379.975.13.641.34137.756.4105.73.645.34107.656.4106.33.4247.28118.096.139.556.93.0647.16128.545.658.717.52.747.04139.015.247.948.12.3446.92149.494.897.238.71.9846.8150.994.576.559.31.6246.7170.54.35.929.91.2646.6181.014.055.3110.50.946.5191.543.834.7311.10.5446.4202.093.644.1811.70.1846.32212.643.463.64表1-3 hi（m）有效长度Li（m）垂直压力Pvi（KN/m²）抗拔力Sfi（KN）侧压力Exi(KN)抗拔系数Ksi0.38.424.9112.554.792.620.98.435.1717.736.752.6271.58.445.4522.918.732.6242.18.455.7628.1010.72.6262.78.466.1033.3012.692.6243.38.476.4538.5314.682.6253.98.486.8343.2416.672.5944.58.497.6349.2118.672.6365.18.4107.6054.2620.672.6255.78.4118.0959.5222.672.6256.38.58128.5450.7523.642.1476.96.94139.0157.8823.582.4557.57.3149.4965.4823.522.7848.17.66159.9973.5323.463.1348.78.02170.5082.0423.43.5069.38.38181.5491.2623.353.9089.98.74191.54100.4423.34.31110.59.1202.09110.3423.254.74611.19.46212.64122.9923.25.30111.79.82223.2131.5123.165.678表1-4 hi（m）抗拔力Sfi（KN）hbi=H-hi（m）Mfi=Sfi*hbi∑MeK00.312.5511.7146.8351772.4162.9250.917.7311.1196.8031.522.9110.5240.5552.128.109.9278.192.733.309.3309.693.338.538.7335.2113.943.248.1350.2444.549.217.5369.0755.154.266.9375.3945.759.526.3373.0866.350.755.7289.2756.957.885.1295.1887.565.484.5294.668.173.533.9286.8068.782.043.3270.7329.391.262.7240.4029.9100.442.1210.92410.5110.341.5165.5111.1122.990.911.69111.7131.510.339.453表1-5 谢谢观看