Page 573 - 水土保持手冊_10612

地基允許壓力 25 t/
2
地基土壤與混凝土間摩擦角為 35˚

[解]1.假設斷面如下圖 附 3-2

1.6
其中tan = = 0.2
8.0
α = 11.3°
∴ λ = α + δ
β = 15°

該混凝土與土壤之摩擦

角
2
δ = � = 20°
3

∴ λ = 11.3° + 20° =
31.3°

sin λ = 0.5195
cos λ = 0.8545

ℎ = sin 15° = 0.26
′

圖 附 3-2 半重力式擋土牆示意圖

庫倫土壓係數

2
(30° − 11.3°)
= 2

sin(30° + 20°) sin(30° − 15°)
cos 11.3° cos(20° + 11.3°) �1 + � �
cos(20° + 11.3°) cos(15° − 11.3°)
2
18.7°
=
2
sin 50° sin 15°
cos 11.3° cos 31.3° �1 + � �
cos 31.3° cos 3.7°

0.8972
=
2
0.7660 × 0.2588
0.9806 × 0.8545 �1 + � �
0.8545 × 0.998

0.8972
= = 0.487
0.9806 × 0.8545 × 2.1972

工-3-15