Page 75 - Buried Pipe Design
P. 75
External Loads 51
Motion
W
P H
Unit Wt.
of Soil
D
El = Wall
Stiffness
Figure 2.28 Sketch of a physical model for evaluating
the wheel load passing over a buried flexible pipe that
dents the top of the pipe.
s = Q/A
P
Q
A = Area
E¢
L
e = Δ/L
Figure 2.29 Confined compression soil test.
3
3
1. (EI/PD ) m (EI/PD )
(H/D)
2. (H/D) m
(P/E′)
3. (P/E′) m
4. ( D/E′) m ( D/E′)
Using subscript r to represent the ratio of prototype to model, each of the
design conditions can be met according to the following:
1. (EI) r P r (D r ) 3 where D r is length scale ratio and P r the pressure ratio
2. (H r ) (D r ) geometric similarity
