【《某公路隧道支护结构设计案例》9200字】

某公路隧道支护结构设计案例目录TOC\o"1-3"\h\u1524某公路隧道支护结构设计案例 错误!未找到引用源。。如图1.39所示，剪力在拱顶处为零，并关于拱顶垂线呈反对称。17.结构验算（1）按偏心要求，对于整体式混凝土衬砌，其偏心受压构件，轴向力的偏心距和截面厚度应满足。（2）按抗压要求，混凝土轴心、偏心受压构件的抗压强度应按下式计算：式中：（3）按抗裂要求，对于混凝土矩形截面，偏心受压构件的抗拉强度按下式计算：式中：当时，系抗压强度控制承载力，可不必按抗裂公式计算；时，系抗拉强度控制承载能力，可不必按抗压计算。①拱顶验算a.偏心验算满足要求。b.抗压验算（可不必计算）满足要求。c.抗裂验算可见左边大于右边（满足）。②侧墙验算a.偏心检验满足要求。b.抗压验算满足要求。c.抗裂验算（可不必计算）③底墙验算a.偏心检验满足要求。b.抗压验算满足要求。c.抗裂验算（可不必计算）18.验算结论本设计按最不利情况，二次衬砌承担100%荷载。经过以上验算，二次衬砌支护结构强度，结构拱顶处满足抗裂和抗压的要求，结构不需需要进行配筋计算。1.3.3Ⅴ级围岩衬砌验算对于Ⅴ级围岩，在根据经验选定支护参数后，仍需进行验算，对于Ⅴ级围岩的内力求解，采用ANSYS12.0软件数值法计算，衬砌设计图1.25，图1.25Ⅴ级围岩衬砌支护设计（单位：cm）1.设计基本资料a.岩体特征岩体为Ⅴ级围岩，围岩的弹性抗力系数，计算摩察角，岩体重度，变形模量，泊松比，粘聚力，内摩察角。b.衬砌材料初衬采用初衬选用C25混凝土；重度，弹性模量，混凝土衬砌轴心抗压强度标准值：，混凝土轴心抗拉强度标准值：。二衬选用C30防水混凝土；重度，弹性模量，混凝土衬砌轴心抗压强度标准值：，混凝土轴心抗拉强度标准值：。2.主动荷载隧道处于Ⅴ级围岩中，为深埋隧道，围岩压力为松散荷载。作用在其结构上的荷载形式为：垂直均布荷载q、水平均布侧向荷载e，侧压力系数0.4。竖向围岩压力水平围岩压力边墙底部水平围岩压力3.内力分析采用荷载结构法进行计算。荷载结构法基本假定：①按平面应变问题进行处理②结构属于小变形③弹簧单元只受压。按照隧道断面几何数据建立分析模型。单元实常数、材料属性，、。单元网格划分：拱部半圆弧划分为50份，边墙每段划分为4份，仰拱划分为20份，一共78个单元。对于拱形结构需要约束墙底的水平位移，同时为避免结构整体沉降过大，使弹簧全部受拉，往往也要对墙底的垂直位移进行约束、本模型选取节点29、52进行约束。首先在CAD中建立模型，根据规范标准断面的建议，建立二次衬砌结构几何模型，然后导入ANSYS。选用Beam单元模拟衬砌结构，对模型施加围岩垂直、水平荷载、重力，围岩、二次衬砌之间施加径向弹簧，添加边墙底端垂直、水平位移约束。数值求解，采用全牛顿-拉普森法，进行分析求解。求解后采用生死单元命令杀死全部受拉弹簧，进行第二次求解。最后，处理数据结构，得到弯矩、轴力、剪力。ANSYS数值分析过程。结构划分见图1.26图1.26单元结构划分对节点施加荷载如图1.27图1.27节点荷载施加对于拱形结构，需要约束墙底的水平位移。同时为避免结构整体沉降过大，使弹簧全部受拉，也要对墙底的垂直位移进行约束、本模型选取节点29，52进行约束。地层弹簧单元，选择单元实常数，长度1m。惯性荷载（重力加速度）Gravity取9.8。施加径向弹簧如图1.28所示。图1.28径向弹簧，墙底约束施加查看求解后的弹簧受力表，分批多次除去受拉弹簧（正值受拉，负值受拉），在重新计算，保证弹簧全部处于受压状态。确定抗力分布范围，最终计算模型。如图1.29所示。图1.29采用生死单元法杀死受拉弹簧后的变形弯矩结果如图1.30图1.30弯矩图轴力图如图1.31图1.31轴力图剪力图如图1.32图1.32剪力图如图1.46所示，最大正弯矩出现在距离拱顶45°两侧，最大负弯矩出现在拱顶位置，弯矩关于拱顶垂线呈轴对称。如图1.47所示，拱墙与上部拱圈轴力值全为负值，即拱墙以上全部受压，其中最大值出现在边墙底角处，最小值出现在拱顶处；拱墙以下与仰拱全部为正值，即全部受拉。轴力关于拱顶垂线呈轴对称。如图1.48所示，剪力在拱顶处为零，并关于拱顶垂线呈反对称。节点坐标与荷载如表1.20表1.20节点坐标与荷载STATCURRENTCURRENTCURRENTCURRENTCURRENTCURRENTELEMNINJQIQJMIMJ1-0.23436E+007-0.23440E+007-37217.0-47202.0-0.13338E+007-0.12922E+0072-0.23683E+007-0.23694E+007-0.11937E+006-0.12930E+006-0.12922E+007-0.11697E+0073-0.24077E+007-0.24096E+007-0.19651E+006-0.20634E+006-0.11697E+007-0.97128E+0064-0.24705E+007-0.24730E+007-0.26386E+006-0.27352E+006-0.97128E+006-0.70659E+0065-0.25546E+007-0.25579E+007-0.31724E+006-0.32668E+006-0.70659E+006-0.38942E+0066-0.26575E+007-0.26614E+007-0.35281E+006-0.36200E+006-0.38942E+006-37334.07-0.27760E+007-0.27806E+007-0.36721E+006-0.37608E+006-37334.00.32878E+0068-0.29064E+007-0.29117E+007-0.35759E+006-0.36609E+0060.32878E+0060.68523E+0069-0.30446E+007-0.30504E+007-0.32169E+006-0.32979E+0060.68523E+0060.10061E+00710-0.31860E+007-0.31925E+007-0.25796E+006-0.26559E+0060.10061E+0070.12640E+00711-0.33261E+007-0.33331E+007-0.16551E+006-0.17265E+0060.12640E+0070.14306E+00712-0.34599E+007-0.34674E+007-44231.0-50843.00.14306E+0070.14774E+00713-0.35827E+007-0.35906E+0070.10524E+00699199.00.14774E+0070.13767E+00714-0.36896E+007-0.36980E+0070.28152E+0060.27609E+0060.13767E+0070.11020E+00715-0.37763E+007-0.37851E+0070.48251E+0060.47770E+0060.11020E+0070.62909E+00616-0.38385E+007-0.38476E+0070.70539E+0060.70125E+0060.62909E+006-63759.017-0.38725E+007-0.38819E+0070.94672E+0060.94326E+006-63759.0-0.99468E+00618-0.38750E+007-0.38846E+0070.12025E+0070.11997E+007-0.99468E+006-0.21779E+00719-0.39362E+007-0.39460E+007-0.13045E+007-0.13066E+007-0.21779E+007-0.89179E+00620-0.40659E+007-0.40758E+007-0.82126E+006-0.82258E+006-0.89179E+006-82102.21-0.41374E+007-0.41473E+007-0.18491E+006-0.18550E+006-82102.00.10035E+00622-0.41574E+007-0.41674E+00753894.054044.00.10035E+00647183.023-0.41622E+007-0.41722E+00771631.072516.047183.0-23818.024-0.41690E+007-0.41788E+0071307.72924.2-23818.0-25903.025-0.41877E+007-0.41974E+007-0.19664E+006-0.19430E+006-25903.00.16666E+00626-0.42482E+007-0.42549E+007-87649.-84789.00.16666E+0060.22884E+00627-0.42235E+007-0.42293E+0070.58572E+0060.59019E+0060.22884E+006-0.19521E+00628-42103.0-46558.0-88901.0-83103.0-0.19521E+006-0.13318E+00629-66162.0-68991.0-68530.0-61781.0-0.13318E+006-86186.030-85459.0-88289.0-53591.0-42766.0-86186.0-33011.031-89408.0-91946.0-40371.0-29473.0-33011.05521.932-0.10331E+006-0.10555E+006-29157.0-18191.05521.9031652.033-0.11671E+006-0.11866E+006-17237.0-6214.531652.044592.034-0.12960E+006-0.13125E+006-4631.76439.644592.043591.035-0.14192E+006-0.14328E+0068642.719754.043591.027921.036-0.15365E+006-0.15471E+00622566.033710.027921.0-3127.5037-0.16476E+006-0.16551E+00637118.048287.0-3127.50-50253.038-0.17661E+006-0.17707E+006-34496.0-23311.0-50253.0-18356.039-0.24342E+006-0.24357E+006-19971.0-8778.4-18356.0-2492.2040-0.24352E+006-0.24337E+00610240.021433.-2492.2-19969.041-0.19909E+006-0.19864E+00626029.037214.0-19969.-54866.042-0.18804E+006-0.18729E+006-51002.0-39833.0-54866.-4744.043-0.17731E+006-0.17625E+006-35818.0-24674.0-4744.028631.044-0.16592E+006-0.16457E+006-21253.0-10142.028631.045958.045-0.15393E+006-0.15228E+006-7328.63742.6045958.047937.046-0.14136E+006-0.13941E+0065936.016959.047937.035304.047-0.12824E+006-0.12600E+00618523.029489.035304.08811.648-0.11462E+006-0.11208E+00630411.041317.08811.60-30770.049-0.11093E+006-0.10810E+00644318.055148.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