Compelo Energy is using cookies

We use them to give you the best experience. If you continue using our website, we'll assume that you are happy to receive all cookies on this website.

ContinueLearn More

Table 1: Assumptions employed in the guides on optimum diameter of diversion tunnel

Type Top width, B (m) Average length, W(m) Average side slope Freeboard, F (m)
Embankment 5 100 to 1200 1H:2.25V 1.5
Length, L (m) Diameter, D (m) Longitudinal slope, S (-) Lining thickness, T(cm)
100 to 1400 3 to 15 0.005 (0.001 to 0.015) 30 to 75, varying linearly with D
Discharge, Q (m3/s) Manning Roughness Coefficient, n Flow regime Exit
50 to 1900 0.014 for RC lining 0.022 for shotcrete 0.030 for natural rock Pressurised (full flow) Unsubmerged
Type I (n=0.014 Type II (n=0.022) Type III (n=0.030) Rock bolts Shotcrete
Rock bolts + Shotcrete + Reinforced concrete (RC) Rock bolts + shotcrete Little rock bolts + little shotcrete ~3m long 10cm thick with steel wires
Tunnel excavation, C1 (US$/m3) Concrete lining C2 (US$/m3) Support (rock bolts + shotcrete), C3 (US$/m2) Fill for the cofferdam, C4 (US$/m3)
8 to 48 40 to 140 24 to 70 2 to 8