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=/3×(2+) /(+)++=5. 78m
=/3×(2+) /(+)+=2.2m
=/2=0.24m
=/3×(2+) /(+)=0.228m
各层土压力转化为集中力
=1.5/2×(9.32+38.3)=35.715 KN/m
=4.7/2×(7.2+59.798)=157.445 KN/m
=59.798×0.48=28.703kN/m
=0.48/2×(44.302+59.798)=24.984 KN/m
取锚杆支点到基坑底的距离 设置弯矩零点所受合弯矩为零
×(
)+
×
=
=4.2m
×+×+×
即0.24
×(4.2+0.48)+24.984×0.228=35.657×5.778+157.448×2.215+28.703×
=119.04KN/m 3、排桩的设计计算
第 5 页 共 36 页
(1)嵌固深度计算;
由
则 (1/2×19×1.698×2/3+44.302× 2/2)+118.796×(4.2+) -1.2×1.0
×[9.298×1.5×(1.5/2+4.7+)+(38.244-9.298)×1.5/2×(1.5/3+4.7+)+
7.201×4.7×(4.7/2+
2/2]≥
)+(58.795-7.201)×4.7/2×(4.7/3+) +59.798×
0
3-13.728
5.377 2-112.715-55.925 ≥ 0
得 ≥6.21m 取=6.3m
灌注桩长(2)结构计算
=6.3+6.2=12.5m
第 6 页 共 36 页
该反弯点C截面剪力最大 =
=118.796-1.5/2×(9.298+38.244) -0.5/2×[(23×1.5+19×0.5+22) ×0.589-2×17×0.767+7.2] =77.84KN 当
+
时假设弯矩最大截面在基坑上部
1/2×(38.244+9.298)×1.5+X/2×[(23×1.5+19X+22)×0.589-2×17×0.767+7.201]=118.796
5.5955X2+7.201X-83.1395=0 X=3.27m 该处最大弯矩为:
=[1/2×(38.244-9.298)×1.5×(1.5/3+3.265)+1/2×3.625×3.625/3×[(23×1.5+19×3.265+22) ×0.589 -2×17×0.767+7.201×2] -(3.265+1.5-2)×118.796 =-88KN.m
假设弯矩最大截面在基坑以下
1/2×(38.244+9.298)×1.5+1/2×(7.201+59.798)×4.7+59.798X=X/2×(19X×1.68+2×17×1.303+44.302)+118.796 16.131X2-15.4955X-74.3082=0 X=2.68m
(该处被动土压力为 19 X×1.698+2×17×1.303=133.99 KN/m2
第 7 页 共 36 页
该处最大弯矩为:
=[ 1/2×(38.244-9.298) ×1.5×(1.5/3+4.7+2.78) +9.298×1.5×(1.5/2+4.7+2.78) +1/2×(59.798-7.201) ×4.7×(4.7/3+2.78)+7.201×4.7×(4.7/2+2.78)+59.798×2.782/2]-[(133.99-44.303)×2.78×1/2×2.78/3+44.302×2.782/2-(4.2+2.78) ×118.796] =114 KN.m ①截面弯矩设计值M
=1.25×1.0×114.83=142.788KN.m
②截面剪力设计值V
=1.25×1.0×78=97.3KN
③支点力设计值
=1.25×1.0×119.04=148.8KN
(3)①截面配筋计算
沿周边均匀配置纵向钢筋。桩身混凝土强度等级为C30,
纵向钢筋采用HRB400,;灌注桩直径为600mm,混凝土保护层
厚度取,桩间距为1000mm;螺旋钢筋级别为HPB300,选用
8@200。
第 8 页 共 36 页
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