Hydraulic Structures: Fourth Edition

Worked Example 3.1

Note that the unit weight of water, (^) w, is taken as 10 kN m^3 throughout
these worked examples.
The profile of an old concrete gravity dam is shown in Fig. 3.23. The
structural competence of the dam is to be reviewed in relation to planned
remedial work.
Design criteria.Normal load combination (NLC): water load (to
design flood level (DFL))self-weightupliftsilt. Uplift: no provision
in original design. Sediment: friction angle, s30°; submerged unit
weight: s15 kN m^3.
Concrete characteristics: core samples.Unit weight, (^) c24 kN m^3 ;
unit shear resistance, c600 kN m^2 ; angle of shearing resistance, c35°.

1. Analyse the stability of the profile with respect to plane X–X for the
   NLC, using shear friction factor, FSF, for sliding stability.


2. Determine the vertical normal stresses and major principal stresses
   at either face.

Solutions

Full uplift applies as no drains are operative. The sediment load, Ka

(1 sins)/(1sins)0.33.

The profile is subdivided into the elements A and B, identified in Fig.

3.23, for convenience.

182 CONCRETE DAM ENGINEERING

Fig. 3.23 Worked examples 3.1 and 3.2