某建筑基坑如圖所示,矩形附加豎向荷載P0的b×1=3m×2m,其擴散角0=45°。砂土的重度γ=20kN/m3,30°,c′=0kPa。試問:
.
A.0.25 B.0.28 C.0.35 D.0.38
A.50 B.60 C.70 D.80
A.4m B.10m C.13m D.15.5m