Hydraulic Structures: Fourth Edition

WORKED EXAMPLES 115

Solutions

1. Core depth 40  6 46 m. Mean ∆cfor core 20 46/2460 kN m^2.
   Therefore

(^) 1c0.5 460 46/10^4 1.06 m (equation (2.30)).
Settlement under core, clay B: at mid-height,
∆B0.95 20  46 874 kN m^2 (equation (2.32)),
(^1) B0.52 m (equation (2.31));
hence the nominal crest level41.6 m AOD.

2. Point 1:∆21.5 20 430 kN m^2. Therefore at mid-height in clay
   A,

∆A0.98 430 421 kN m^2 (equation (2.32)),

(^1) A0.20 m (equation (2.31)),
and in clay B,
∆B0.95 430 408.5 kN m^2 ,
(^1) B0.25 m.
Therefore (^) total0.45 m at point 1.
Point 2: ∆21.5 40 860 kN m^2. Therefore (^) total0.90 m at
point 2.
Point 3: ∆ 20  40 800 kN m^2. Therefore ∆ in cut-off
0.98 800 784 kN m^2 ,
(^) cin cut-off0.24 m
and∆B0.95 800 760 kN m^2. (6 m depth cut-off balances 6 m
excavated in clay A.) Therefore,
(^) B0.46 m.

0.6 760  10



104

0.6784.6



104

0.6408.5 10



109

0.8 421  6



104

0.6 874  10



104