首罐混凝土
![](http://img.examk.com/exam/x/q/1LBcJ7StHjM42H442dcqedeGQaaruP31.jpg)
V≥1/4πD2·(H1+H2)+1/4πd2·h1
h1=ρ1Hw/ρ2
h1:桩孔内混凝土达到埋置深度H2时,导管内混凝土柱平衡导管外泥浆压力所需的高度
ρ1:泥浆密度,取1.1kg/m3
ρ2:混凝土密度,取2.4kg/m3
Hw:孔内泥浆高度,Hw=L-(H1+H2)
本题Hw=18-(0.5+2)=15.5m
h1=(1.1×15.5)/2.4=7.10m
V≥0.25×3.14×1.2×1.2×2.5+0.25×3.14×0.2×0.2×7.1=2.826+0.223=3.05m3