Page 156 - Buried Pipe Design
P. 156
130 Chapter Three
A
P H H
Wedge D
Z
X
B
Figure 3.27 Vertical trench wall parallel to a buried flexible pipe show-
ing the soil wedge and shear planes that form as the pipe collapses.
Soil
Prism
Wedge Deflected Ring
Figure 3.28 Formation of a soil prism on the pipe as a collapse
mechanism forms.
ring stiffness has no effect anyway. The remaining fundamental vari-
ables are as follows:
Fundamental variables Basic dimensions
X minimum side cover (minimum horizontal separation
between pipe and trench at collapse) L
D pipe diameter L
H height of soil cover over top of pipe L
Z critical depth of trench in vertical cut (vertical sidewalls) L
