喷锚支护计算书.doc

.计算公式和系数等取自建筑施工计算手册（第二版）173页本工程计算参数：土方为粉质粘土，重度=19.70KN/M3 内按摩角=20，粘聚力C=28.50Kpa,地基承载力特征值fak=144Kpa,基坑开挖高度H=7.80米,土钉倾角是10度，Sx水平间距1米，Sy竖向间距，取1.5米，土方侧压力P=28.50(19.707.8)=0.1850.050.05的粘土Ka=0.406, =0.637=0.4061-(228.50)(19.707.80)(10.637)19.707.80=0.4061-(57153.66)1.569153.66=26.20KN/M2=0.40610=4.06 KN/M2=30.26KN/m2土钉所受的拉力N（由上而下1-4道拉杆）N1-4=(1cos)pSxSy=(1cos10)30.261.001.50=（10.9848）30.261.001.50=46.09KNN5=(1cos)pSxSy=(1cos10)30.261.000.30=9.21KN土钉墙安全系统Fsd=1.30土钉在破坏面一侧伸入稳定土体中的长度laLa=(1.3046.09)(3.140.150)=59.91715.70=3.81mLa5=(1.309.21)(3.140.150)=11.97315.70=0.76ml5=tan(86-45+4.70/2)0.30= tan38.650.30=0.79970.30=0.239ml4=tan(86-45+4.70/2)1.80= tan38.651.80=0.79971.8=1.44ml3=tan(86-45+4.70/2)3.30= tan38.651.80=0.79973.30=2.64 ml2=tan(86-45+4.70/2)4.80= tan38.654.80=0.79974.80=3.8356ml1=tan(86-45+4.70/2)6.30= tan38.656.30=0.79976.30=5.00mL=Ln+LaL5=0.76+0.239=0.999=1.00m L4=1.44+3.81=5.25=5.5mL3=2.64+3.81=6.45=6.50m L2=3.84+3.81=7.65=8.00mL1=5.00+3.81=8.81=9.00m土钉墙钢筋直径d钢筋采用HRB335，取y=335N/mm2d= (41.344.71000)(1.13.14335)= (2324401157.09)= 200.88=14.17mm用16钢筋边坡喷砼面层计算在土体自重及地表均布荷载Q作用下，喷砼面层所受的侧向土压力为P01=0.700.50+(1.5-0.5)526.20 =0.700.50+0.2026.20 =12.838KN/M2 P0=1.2（12.838+4.06）=20.2776 KN/M2按四边简支板形式配制钢筋：lx/ly=1/1.5=0.666查简支双向板系数：W=0.007753 Kx=0.069732 Ky=0.02785Qx=1.420.2776=28.388KN/m=0.069728.38810002=19.78105KN.mm计算选筋： c=11.9(C25砼)喷射砼面厚度为100mm，则h0=80mmas=(19.78105)(11.91000802)= (19.78105)（761601000）=0.0259查表=0.9875，采用HRB235钢筋，y=210N/mm2As=(19.78105)(800.9875210)= (19.78105)16590=119.19mm2采用6200（141mm2）竖向配筋 Qy=20.27761.0=20.2776KN/M = 0.027920.277615001500=12.73105N.mmAs= 12.73105(800.9905210)= 12.7310516640.4=76.5mm2采用6200（141mm2）边坡稳定性验算设土体墙宽度5m（按墙宽一般取基坑深度的0.4-0.8）1.2F1=（7.8519.7+510）tan20=(768.3+50)0.3639=304.32KNN=46.094+9.21=193.57KNK1=F1N=304.32193.57=1.5721.2所以边坡稳定。抗倾覆验算：土的自重平衡力矩： 1.3Mw=(7.8519.